gulp.js環境で、jadeの中でjsonから定型文を呼び出す、2ヶ国語(ja/en)バージョン ref: http://qiita.com/sakadon/items/692ecb29b24b8db20ef3

gulp.js

var gulp = require('gulp');
var plumber = require('gulp-plumber');
var jade = require('gulp-jade');
var data = require('gulp-data');

// Jade compile to html
gulp.task( 'jade', function() {
    gulp.src( './src/jade/*.jade' )
    .pipe( data( function (file) {
        return { 'meta': require('./src/jade/meta.json')};
    }) )
    .pipe( plumber() )
    .pipe( jade({
        pretty: true
    }) )
    .pipe( gulp.dest('./public_html') )
    .pipe( browserSync.reload({
        stream: true
    }) );
});

index.en.jade

doctype html
html
    head
        meta(charset="utf-8")
        block title
            title #{meta.en.title}
        meta(name="description", content=meta.en.description)
        meta(name="keywords", content=meta.en.keywords)
        meta(property="og:title", content=meta.en.title)
        meta(property="og:type", content="website")
        meta(property="og:url", content=meta.en.url)
        meta(property="og:image", content=meta.en.image)
        meta(property="og:site_name", content=meta.en.site_name)
        meta(property="og:description", content=meta.en.description)
        link(rel="stylesheet", href="style.css")
        script(src="/js/modernizr.js")
        script(src="/js/jquery.min.js")
    body
    ...

index.ja.jade

doctype html
html
    head
        meta(charset="utf-8")
        block title
            title #{meta.ja.title}
        meta(name="description", content=meta.ja.description)
        meta(name="keywords", content=meta.ja.keywords)
        meta(property="og:title", content=meta.ja.title)
        meta(property="og:type", content="website")
        meta(property="og:url", content=meta.ja.url)
        meta(property="og:image", content=meta.ja.image)
        meta(property="og:site_name", content=meta.ja.site_name)
        meta(property="og:description", content=meta.ja.description)
        link(rel="stylesheet", href="style.css")
        script(src="/js/modernizr.js")
        script(src="/js/jquery.min.js")
    body
    ...

meta.json

{
    "ja": {
        "title":        "日本語タイトル",
        "description":  "詳細",
        "keywords":     "ほげ,ふが",
        "url":          "http://",
        "image":        "http://",
        "site_name":    "日本語サイトネーム"
    },
    "en": {
        "title":        "EnglishTitle",
        "description":  "Description",
        "keywords":     "Hoge,Fuga",
        "url":          "http://",
        "image":        "http://",
        "site_name":    "EnglishSitename"
    }
}