diff --git a/.eslintrc.js b/.eslintrc.js
index 0894c8643..4a9f347a3 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -23,6 +23,7 @@ module.exports = {
         'import/extensions': 'off',
         'import/no-cycle': 'off',
         'import/no-extraneous-dependencies': 'off',
+        'import/no-named-as-default': 'off',
         'import/no-named-as-default-member': 'off',
         'import/prefer-default-export': 'off',
         indent: ['warn', 4],
diff --git a/packages/hydrojudge/locales/zh_CN.yaml b/packages/hydrojudge/locales/zh_CN.yaml
new file mode 100644
index 000000000..39fdc910b
--- /dev/null
+++ b/packages/hydrojudge/locales/zh_CN.yaml
@@ -0,0 +1,26 @@
+'Error parsing memory: {0}': 无法解析内存：{0}
+'Error parsing time: {0}': 无法解析时间：{0}
+Cannot connect to sandbox service.: 无法连接到沙箱服务。
+Cannot find checker {0}.: 找不到比较器 {0}。
+Cannot find input file {0}.: 找不到输入文件 {0}。
+Cannot find judge extra file {0}.: 找不到评测额外文件 {0}。
+Cannot find output file {0}.: 找不到输出文件 {0}。
+Cannot find user extra file {0}.: 找不到用户额外文件 {0}。
+Cannot parse testdata.: 无法解析测试数据。
+Checker returned {0}.: 比较器返回了{0}。
+Executable file not found.: 没有找到可执行文件。
+Found {0} testcases.: 识别到 {0} 个测试点。
+Invalid judge_extra_files config.: 无效的 judge_extra_files 配置。
+Invalid user_extra_files config.: 无效的 user_extra_files 配置。
+Problem data not found.: 没有找到测试数据。
+Read {0}, expect {1}.: 读取到 {0}，应为 {1}。
+Standard answer longer than user output.: 标准输出比选手输出长。
+Testdata configuration incorrect.: 题目配置错误。
+Too many files.: 文件过多。
+Too many testcases. Cancelled.: 测试数据过多。评测取消。
+Total time limit longer than 60s. Cancelled.: 总时限超过60s。评测取消。
+Unknown checker type {0}.: 未知的比较器类型 {0}。
+Unknown language type.: 未知的语言类型。
+Unsupported language {0}.: 不支持的语言 {0}。
+User output longer than standard answer.: 选手输出比标准输出长。
+Your program returned {0}.: 您的程序返回了{0}。
\ No newline at end of file
diff --git a/packages/hydrojudge/package.json b/packages/hydrojudge/package.json
index 181c92023..18f559ff3 100644
--- a/packages/hydrojudge/package.json
+++ b/packages/hydrojudge/package.json
@@ -1,7 +1,7 @@
 {
     "name": "@hydrooj/hydrojudge",
     "bin": "bin/hydrojudge.js",
-    "version": "2.1.25",
+    "version": "2.1.26",
     "main": "package.json",
     "author": "masnn",
     "repository": "https://github.com/hydro-dev/Hydro.git",
diff --git a/packages/hydrojudge/src/cases.ts b/packages/hydrojudge/src/cases.ts
index 17ff02178..a4a68e5a7 100644
--- a/packages/hydrojudge/src/cases.ts
+++ b/packages/hydrojudge/src/cases.ts
@@ -186,9 +186,9 @@ async function readAutoCases(folder, { next }) {
         let result = await read0(folder, files, checkFile);
         if (!result.count) result = await read1(folder, files, checkFile);
         Object.assign(config, result);
-        next({ message: `识别到${config.count}个测试点` });
+        next({ message: { message: 'Found {0} testcases.', params: config.count } });
     } catch (e) {
-        throw new SystemError('在自动识别测试点的过程中出现了错误。', [e]);
+        throw new SystemError('Cannot parse testdata.', [e]);
     }
     return config;
 }
@@ -204,24 +204,24 @@ export async function readYamlCases(folder: string, cfg: Dictionary<any> = {}, a
     const next = args.next;
     const checkFile = ensureFile(folder);
     config.checker_type = cfg.checker_type || 'default';
-    if (cfg.checker) config.checker = checkFile(cfg.checker, '找不到比较器 ');
+    if (cfg.checker) config.checker = checkFile(cfg.checker, 'Cannot find checker {0}.');
     if (cfg.judge_extra_files) {
         if (typeof cfg.judge_extra_files === 'string') {
-            config.judge_extra_files = [checkFile(cfg.judge_extra_files, '找不到评测额外文件 ')];
+            config.judge_extra_files = [checkFile(cfg.judge_extra_files, 'Cannot find judge extra file {0}.')];
         } else if (cfg.judge_extra_files instanceof Array) {
             for (const file of cfg.judge_extra_files) {
-                config.judge_extra_files.push(checkFile(file, '找不到评测额外文件 '));
+                config.judge_extra_files.push(checkFile(file, 'Cannot find judge extra file {0}.'));
             }
-        } else throw new FormatError('无效的 judge_extra_files 配置项');
+        } else throw new FormatError('Invalid judge_extra_files config.');
     }
     if (cfg.user_extra_files) {
         if (typeof cfg.user_extra_files === 'string') {
-            config.user_extra_files = [checkFile(cfg.user_extra_files, '找不到用户额外文件 ')];
+            config.user_extra_files = [checkFile(cfg.user_extra_files, 'Cannot find user extra file {0}.')];
         } else if (cfg.user_extra_files instanceof Array) {
             for (const file of cfg.user_extra_files) {
-                config.user_extra_files.push(checkFile(file, '找不到用户额外文件 '));
+                config.user_extra_files.push(checkFile(file, 'Cannot find user extra file {0}.'));
             }
-        } else throw new FormatError('无效的 user_extra_files 配置项');
+        } else throw new FormatError('Invalid user_extra_files config.');
     }
     if (cfg.cases) {
         config.subtasks = [{
@@ -234,8 +234,8 @@ export async function readYamlCases(folder: string, cfg: Dictionary<any> = {}, a
         for (const c of cfg.cases) {
             config.count++;
             config.subtasks[0].cases.push({
-                input: checkFile(c.input, '找不到输入文件 '),
-                output: checkFile(c.output, '找不到输出文件 '),
+                input: checkFile(c.input, 'Cannot find input file {0}.'),
+                output: checkFile(c.output, 'Cannot find output file {0}.'),
                 id: config.count,
             });
         }
@@ -245,8 +245,8 @@ export async function readYamlCases(folder: string, cfg: Dictionary<any> = {}, a
             for (const c of subtask.cases) {
                 config.count++;
                 cases.push({
-                    input: checkFile(c.input, '找不到输入文件 '),
-                    output: checkFile(c.output, '找不到输出文件 '),
+                    input: checkFile(c.input, 'Cannot find input file {0}.'),
+                    output: checkFile(c.output, 'Cannot find output file {0}.'),
                     id: config.count,
                 });
             }
@@ -284,12 +284,12 @@ function convertIniConfig(ini: string) {
 }
 
 function isValidConfig(config) {
-    if (config.count > 100) throw new FormatError('测试数据组数过多，拒绝评测');
+    if (config.count > 100) throw new FormatError('Too many testcases. Cancelled.');
     let total_time = 0;
     for (const subtask of config.subtasks) {
         total_time += subtask.time_limit_ms * subtask.cases.length;
     }
-    if (total_time > 60 * 1000) throw new FormatError('总时限超过限制60s，拒绝评测');
+    if (total_time > 60 * 1000) throw new FormatError('Total time limit longer than 60s. Cancelled.');
 }
 
 export default async function readCases(folder: string, cfg: Record<string, any> = {}, args) {
diff --git a/packages/hydrojudge/src/check.ts b/packages/hydrojudge/src/check.ts
index 4c67e1f0c..72ba8e992 100644
--- a/packages/hydrojudge/src/check.ts
+++ b/packages/hydrojudge/src/check.ts
@@ -17,12 +17,12 @@ export async function check(config): Promise<[number, number, string]> {
         copyIn: config.copyIn || {},
         detail: config.detail,
     });
-    if (code) throw new SystemError(`比较器返回了非零值：${code}`);
+    if (code) throw new SystemError('Checker returned {0}.', [code]);
     return [status, score, message];
 }
 
 export async function compileChecker(checkerType: string, checker: string, copyIn: any) {
-    if (!checkers[checkerType]) throw new SystemError(`未知比较器类型：${checkerType}`);
+    if (!checkers[checkerType]) throw new SystemError('Unknown checker type {0}.', [checkerType]);
     const file = await fs.readFile(checker);
     // TODO cache compiled checker
     return await compile(parseFilename(checker).split('.')[1], file.toString(), 'checker', copyIn);
diff --git a/packages/hydrojudge/src/checkers.ts b/packages/hydrojudge/src/checkers.ts
index bb305f3f7..9d9e4e059 100644
--- a/packages/hydrojudge/src/checkers.ts
+++ b/packages/hydrojudge/src/checkers.ts
@@ -23,7 +23,7 @@ const checkers: Record<string, Checker> = {
             },
         });
         let status;
-        let message = '';
+        let message: any = '';
         if (stdout) {
             status = STATUS.STATUS_WRONG_ANSWER;
             if (config.detail) {
@@ -33,8 +33,8 @@ const checkers: Record<string, Checker> = {
                     let usr = u.substr(2, u.length - 2).trim().split(' ');
                     const t = pt[1].split('\n')[1];
                     let std = t.substr(2, t.length - 2).trim().split(' ');
-                    if (usr.length < std.length) message = '标准输出比选手输出长。';
-                    else if (usr.length > std.length) message = '选手输出比标准输出长。';
+                    if (usr.length < std.length) message = 'Standard answer longer than user output.';
+                    else if (usr.length > std.length) message = 'User output longer than standard answer.';
                     else {
                         for (const i in usr) {
                             if (usr[i] !== std[i]) {
@@ -45,7 +45,7 @@ const checkers: Record<string, Checker> = {
                         }
                         if (usr.length > 20) usr = `${usr.substring(0, 16)}...`;
                         if (std.length > 20) std = `${std.substring(0, 16)}...`;
-                        message = `读取到 ${usr} ，应为 ${std}`;
+                        message = { message: 'Read {0}, expect {1}.', params: [usr, std] };
                     }
                 } catch (e) {
                     message = stdout.substring(0, stdout.length - 1 <= 30 ? stdout.length - 1 : 30);
diff --git a/packages/hydrojudge/src/compile.ts b/packages/hydrojudge/src/compile.ts
index 1f2d8af37..725fcca53 100644
--- a/packages/hydrojudge/src/compile.ts
+++ b/packages/hydrojudge/src/compile.ts
@@ -11,7 +11,7 @@ export = async function compile(
     const LANGS = global.Hydro
         ? yaml.safeLoad(await global.Hydro.model.system.get('hydrojudge.langs'))
         : require('./config').LANGS;
-    if (!LANGS[lang]) throw new SystemError(`不支持的语言：${lang}`);
+    if (!LANGS[lang]) throw new SystemError('Unsupported language {0}.', [lang]);
     const info = LANGS[lang];
     target = info.target || target;
     const f = {};
@@ -24,7 +24,7 @@ export = async function compile(
             { copyIn, copyOutCached: [target] },
         );
         if (status !== STATUS.STATUS_ACCEPTED) throw new CompileError({ status, stdout, stderr });
-        if (!fileIds[target]) throw new CompileError({ stderr: '没有找到可执行文件' });
+        if (!fileIds[target]) throw new CompileError({ stderr: 'Executable file not found.' });
         if (next) next({ compiler_text: compilerText(stdout, stderr) });
         f[target] = { fileId: fileIds[target] };
         return {
@@ -36,5 +36,5 @@ export = async function compile(
             execute: info.execute, copyIn: f, clean: () => Promise.resolve(), time: info.time || 1,
         };
     }
-    throw new SystemError('Unknown language type');
+    throw new SystemError('Unknown language type.');
 }
diff --git a/packages/hydrojudge/src/hosts/hydro.ts b/packages/hydrojudge/src/hosts/hydro.ts
index d044f5cdf..21c20785b 100644
--- a/packages/hydrojudge/src/hosts/hydro.ts
+++ b/packages/hydrojudge/src/hosts/hydro.ts
@@ -4,6 +4,7 @@ import axios from 'axios';
 import AdmZip from 'adm-zip';
 import fs from 'fs-extra';
 import WebSocket from 'ws';
+import { argv } from 'yargs';
 import { noop } from 'lodash';
 import { ObjectID } from 'bson';
 import * as tmpfs from '../tmpfs';
@@ -89,14 +90,14 @@ class JudgeTask {
                     status: STATUS_COMPILE_ERROR, score: 0, time_ms: 0, memory_kb: 0,
                 });
             } else if (e instanceof FormatError) {
-                this.next({ judge_text: '题目配置出现错误。请联系题目上传者。' });
-                this.next({ judge_text: `${e.message}\n${JSON.stringify(e.params)}` });
+                this.next({ judge_text: 'Testdata configuration incorrect.' });
+                this.next({ judge_text: { message: e.message, params: e.params } });
                 this.end({
                     status: STATUS_SYSTEM_ERROR, score: 0, time_ms: 0, memory_kb: 0,
                 });
             } else {
                 log.error(e);
-                this.next({ judge_text: `${e.message}\n${e.stack}\n${JSON.stringify(e.params)}` });
+                this.next({ message: { message: e.message, params: e.params, ...argv.debug ? { stack: e.stack } : {} } });
                 this.end({
                     status: STATUS_SYSTEM_ERROR, score: 0, time_ms: 0, memory_kb: 0,
                 });
diff --git a/packages/hydrojudge/src/hosts/vj4.ts b/packages/hydrojudge/src/hosts/vj4.ts
index bef488d8c..a66c64bec 100644
--- a/packages/hydrojudge/src/hosts/vj4.ts
+++ b/packages/hydrojudge/src/hosts/vj4.ts
@@ -134,10 +134,16 @@ class JudgeTask {
             data.judge_text = data.message;
             delete data.message;
         }
+        if (data.judge_text && typeof data.judge_text !== 'string') {
+            data.judge_text = `${data.judge_text.message} ${JSON.stringify(data.judge_text.params || {})}`;
+        }
         if (data.case?.message !== undefined) {
             data.case.judge_text = data.case.message;
             delete data.case.message;
         }
+        if (data.case?.judge_text && typeof data.case?.judge_text !== 'string') {
+            data.case.judge_text = `${data.case.judge_text.message} ${JSON.stringify(data.case.judge_text.params || {})}`;
+        }
         data.key = 'next';
         data.tag = this.tag;
         if (id) {
diff --git a/packages/hydrojudge/src/judge/default.ts b/packages/hydrojudge/src/judge/default.ts
index dc0f33c9f..1b0c03aca 100644
--- a/packages/hydrojudge/src/judge/default.ts
+++ b/packages/hydrojudge/src/judge/default.ts
@@ -42,7 +42,7 @@ function judgeCase(c) {
         if (res.files[`${filename}.out`] || !fs.existsSync(stdout)) {
             fs.writeFileSync(stdout, res.files[`${filename}.out`] || '');
         }
-        let message = '';
+        let message: any = '';
         let score = 0;
         if (status === STATUS.STATUS_ACCEPTED) {
             if (time_usage_ms > ctxSubtask.subtask.time_limit_ms * ctx.execute.time) {
@@ -64,7 +64,7 @@ function judgeCase(c) {
             }
         } else if (status === STATUS.STATUS_RUNTIME_ERROR && code) {
             if (code < 32) message = signals[code];
-            else message = `您的程序返回了 ${code}.`;
+            else message = { message: 'Your program returned {0}.', params: [code] };
         }
         ctxSubtask.score = Score[ctxSubtask.subtask.type](ctxSubtask.score, score);
         ctxSubtask.status = Math.max(ctxSubtask.status, status);
@@ -105,7 +105,7 @@ function judgeSubtask(subtask) {
 }
 
 export const judge = async (ctx) => {
-    if (!ctx.config.subtasks.length) throw new SystemError('没有找到测试数据');
+    if (!ctx.config.subtasks.length) throw new SystemError('Problem data not found.');
     if (ctx.config.template) {
         if (ctx.config.template[ctx.lang]) {
             const tpl = ctx.config.template[ctx.lang];
diff --git a/packages/hydrojudge/src/judge/interactive.ts b/packages/hydrojudge/src/judge/interactive.ts
index 7b32e795d..3a7df1037 100644
--- a/packages/hydrojudge/src/judge/interactive.ts
+++ b/packages/hydrojudge/src/judge/interactive.ts
@@ -30,7 +30,7 @@ function judgeCase(c) {
         ]);
         let status;
         let score = 0;
-        let message = '';
+        let message: any = '';
         if (time_usage_ms > ctxSubtask.subtask.time_limit_ms) {
             status = STATUS.STATUS_TIME_LIMIT_EXCEEDED;
         } else if (memory_usage_kb > ctxSubtask.subtask.memory_limit_mb * 1024) {
@@ -38,7 +38,7 @@ function judgeCase(c) {
         } else if (code) {
             status = STATUS.STATUS_RUNTIME_ERROR;
             if (code < 32) message = signals[code];
-            else message = `您的程序返回了 ${code}.`;
+            else message = { message: 'Your program returned {0}.', params: [code] };
         } else [status, score, message] = resInteractor.files.stderr.split('\n');
         ctxSubtask.score = Score[ctxSubtask.subtask.type](ctxSubtask.score, score);
         ctxSubtask.status = Math.max(ctxSubtask.status, status);
diff --git a/packages/hydrojudge/src/judge/run.ts b/packages/hydrojudge/src/judge/run.ts
index 193d348b2..12d1da7ba 100644
--- a/packages/hydrojudge/src/judge/run.ts
+++ b/packages/hydrojudge/src/judge/run.ts
@@ -31,7 +31,7 @@ export const judge = async (ctx) => {
     const { code, time_usage_ms, memory_usage_kb } = res;
     let { status } = res;
     if (!fs.existsSync(stdout)) fs.writeFileSync(stdout, '');
-    let message = fs.readFileSync(stdout).toString() + fs.readFileSync(stderr).toString();
+    let message: any = fs.readFileSync(stdout).toString() + fs.readFileSync(stderr).toString();
     if (status === STATUS.STATUS_ACCEPTED) {
         if (time_usage_ms > ctx.config.time) {
             status = STATUS.STATUS_TIME_LIMIT_EXCEEDED;
@@ -41,7 +41,7 @@ export const judge = async (ctx) => {
     } else if (code) {
         status = STATUS.STATUS_RUNTIME_ERROR;
         if (code < 32) message += signals[code];
-        else message += `您的程序返回了 ${code}.`;
+        else message = { message: 'Your program returned {0}.', params: [code] };
     }
     ctx.next({
         status,
diff --git a/packages/hydrojudge/src/sandbox.ts b/packages/hydrojudge/src/sandbox.ts
index 964a8ea87..92916519a 100644
--- a/packages/hydrojudge/src/sandbox.ts
+++ b/packages/hydrojudge/src/sandbox.ts
@@ -65,7 +65,7 @@ export async function runMultiple(execute) {
         body.cmd[1].files[1] = null;
         res = await axios.post('/run', body);
     } catch (e) {
-        throw new SystemError('Cannot connect to sandbox service');
+        throw new SystemError('Cannot connect to sandbox service.');
     }
     return res.data;
 }
@@ -86,7 +86,7 @@ export async function run(execute, params?) {
         [result] = res.data;
     } catch (e) {
         // FIXME request body larger than maxBodyLength limit
-        throw new SystemError('Cannot connect to sandbox service ', e.message);
+        throw new SystemError('Cannot connect to sandbox service.', e.message);
     }
     // FIXME: Signalled?
     const ret: any = {
diff --git a/packages/hydrojudge/src/service.ts b/packages/hydrojudge/src/service.ts
index 65bacc111..e52fdf85d 100644
--- a/packages/hydrojudge/src/service.ts
+++ b/packages/hydrojudge/src/service.ts
@@ -2,11 +2,19 @@
 /* eslint-disable no-await-in-loop */
 import 'hydrooj';
 import path from 'path';
+import { argv } from 'yargs';
 import { ObjectID } from 'bson';
 import fs from 'fs-extra';
 import { homedir, tmpdir } from 'os';
 import AdmZip from 'adm-zip';
 import { noop } from 'lodash';
+import { Logger } from 'hydrooj/dist/logger';
+import * as monitor from 'hydrooj/dist/service/monitor';
+import * as tmpfs from './tmpfs';
+import { FormatError, CompileError, SystemError } from './error';
+import { STATUS_COMPILE_ERROR, STATUS_SYSTEM_ERROR } from './status';
+import { compilerText } from './utils';
+import readYamlCases from './cases';
 
 declare module 'hydrooj/dist/interface' {
     interface SystemKeys {
@@ -14,22 +22,16 @@ declare module 'hydrooj/dist/interface' {
     }
 }
 
+const logger = new Logger('judge');
+
 async function postInit() {
     // Only start a single daemon
     if (!global.Hydro.isFirstWorker) return;
-    const { compilerText } = require('./utils');
-    const tmpfs = require('./tmpfs');
-    const { FormatError, CompileError, SystemError } = require('./error');
-    const { STATUS_COMPILE_ERROR, STATUS_SYSTEM_ERROR } = global.Hydro.model.builtin.STATUS;
-    const { default: readYamlCases } = require('./cases');
     const judge = require('./judge');
     const sysinfo = require('./sysinfo');
 
     const { problem, file, task } = global.Hydro.model;
     const _judge = global.Hydro.handler.judge as any;
-    const { monitor } = global.Hydro.service;
-    const { Logger } = global.Hydro.Logger;
-    const logger = new Logger('judge');
 
     const info = await sysinfo.get();
     monitor.updateJudger(info);
@@ -76,7 +78,7 @@ async function postInit() {
         fs.ensureDirSync(path.dirname(savePath));
         const zip = new AdmZip(tmpFilePath);
         const entries = zip.getEntries();
-        if (entries.length > 256) throw new FormatError('Too many files');
+        if (entries.length > 256) throw new FormatError('Too many files.');
         await new Promise((resolve, reject) => {
             zip.extractAllToAsync(savePath, true, (e) => {
                 if (e) reject(e);
@@ -227,13 +229,13 @@ async function postInit() {
                         status: STATUS_COMPILE_ERROR, score: 0, time_ms: 0, memory_kb: 0,
                     });
                 } else if (e instanceof FormatError) {
-                    this.next({ message: `${e.message}\n${JSON.stringify(e.params)}` });
+                    this.next({ message: { message: e.message, params: e.params } });
                     this.end({
                         status: STATUS_SYSTEM_ERROR, score: 0, time_ms: 0, memory_kb: 0,
                     });
                 } else {
                     logger.error(e);
-                    this.next({ message: `${e.message}\n${e.stack}\n${JSON.stringify(e.params)}` });
+                    this.next({ message: { message: e.message, params: e.params, ...argv.debug ? { stack: e.stack } : {} } });
                     this.end({
                         status: STATUS_SYSTEM_ERROR, score: 0, time_ms: 0, memory_kb: 0,
                     });
diff --git a/packages/hydrojudge/src/utils.ts b/packages/hydrojudge/src/utils.ts
index ba8934f57..f75a03f3d 100644
--- a/packages/hydrojudge/src/utils.ts
+++ b/packages/hydrojudge/src/utils.ts
@@ -17,13 +17,13 @@ export function noop() { }
 
 export function parseTimeMS(str: string) {
     const match = TIME_RE.exec(str);
-    if (!match) throw new FormatError(str, ['error parsing time']);
+    if (!match) throw new FormatError('Error parsing time: {0}', [str]);
     return Math.floor(parseFloat(match[1]) * TIME_UNITS[match[2]]);
 }
 
 export function parseMemoryMB(str: string) {
     const match = MEMORY_RE.exec(str);
-    if (!match) throw new FormatError(str, ['error parsing memory']);
+    if (!match) throw new FormatError('Error parsing memory: {0}', [str]);
     return Math.floor(parseFloat(match[1]) * MEMORY_UNITS[match[2]]);
 }
 
@@ -110,9 +110,9 @@ export function restrictFile(p: string) {
 export function ensureFile(folder: string) {
     return (file: string, message: string) => {
         const f = path.join(folder, restrictFile(file));
-        if (!fs.existsSync(f)) throw new FormatError(message + file);
+        if (!fs.existsSync(f)) throw new FormatError(message, [file]);
         const stat = fs.statSync(f);
-        if (!stat.isFile()) throw new FormatError(message + file);
+        if (!stat.isFile()) throw new FormatError(message, [file]);
         return f;
     };
 }