What are Source and Target Languages?
In translation and localization, source language refers to the original language of the content being translated, while target language is the language the content is being translated into.
These fundamental concepts form the basis of all translation work:
- Source (SL): Where the translation starts
- Target (TL): Where the translation ends
Language Codes
ISO Standards
| Standard | Format | Example |
|---|---|---|
| ISO 639-1 | 2-letter | en, de, fr, ru, zh |
| ISO 639-2 | 3-letter | eng, deu, fra, rus, zho |
| BCP 47 | Language-Region | en-US, de-DE, zh-CN |
Common Language Codes
| Language | ISO 639-1 | BCP 47 Variants |
|---|---|---|
| English | en | en-US, en-GB, en-AU |
| German | de | de-DE, de-AT, de-CH |
| French | fr | fr-FR, fr-CA, fr-BE |
| Spanish | es | es-ES, es-MX, es-AR |
| Chinese | zh | zh-CN, zh-TW, zh-HK |
| Russian | ru | ru-RU |
| Japanese | ja | ja-JP |
| Korean | ko | ko-KR |
| Arabic | ar | ar-SA, ar-EG, ar-AE |
| Portuguese | pt | pt-BR, pt-PT |
Language Pairs
A language pair describes the source and target language combination, written as:
EN > DE(English to German)EN-DEorEN→DE(alternative notations)
Common Language Pairs
High-Volume Pairs:
- EN > ZH (English to Chinese)
- EN > ES (English to Spanish)
- EN > JA (English to Japanese)
- EN > DE (English to German)
- EN > FR (English to French)
Regional Pairs:
- EN > PT-BR (English to Brazilian Portuguese)
- EN > ES-MX (English to Mexican Spanish)
- EN > ZH-CN (English to Simplified Chinese)
Directionality
| Term | Meaning | Example |
|---|---|---|
| Into | Translating into your native language | EN > RU (for Russian native) |
| Out of | Translating from your native language | RU > EN (for Russian native) |
| Bi-directional | Working both directions | EN <> RU |
Language Considerations
Source Language Quality
Source quality directly impacts translation:
- Clear, well-written source = better translation
- Ambiguous source = potential errors
- Technical jargon needs documentation
Source Preparation Best Practices:
- Review source for clarity
- Provide context/reference materials
- Document abbreviations and acronyms
- Include style guidelines
Target Language Variations
Regional Variants:
- Spanish: Spain vs. Latin America vs. specific countries
- Portuguese: Brazil vs. Portugal
- Chinese: Simplified vs. Traditional
- English: UK vs. US vs. AU
Considerations:
- Vocabulary differences
- Spelling conventions
- Cultural references
- Date/number formats
- Currency symbols
In CAT Tools
Language Settings
Project Configuration:
- Source Language: en-US
- Target Languages:
- de-DE (German - Germany)
- fr-FR (French - France)
- ja-JP (Japanese - Japan)
- zh-CN (Chinese - Simplified)
Multi-Language Projects
CAT tools handle multiple target languages:
| Approach | Description |
|---|---|
| Single target | One project per language |
| Multi-target | One project, multiple targets |
| Hybrid | Grouped by region/priority |
Translation Direction
Into Native Language (Recommended)
Translating into your native language produces higher quality:
- Better fluency and naturalness
- Accurate idiomatic expressions
- Cultural appropriateness
Out of Native Language
Translating from your native language:
- Perfect source understanding
- May lack target fluency
- Useful for rare language pairs
Best Practice
For quality-critical content:
- Translator: Source → Native Target
- Reviewer: Native in Target Language
Language-Specific Challenges
Script Differences
| Script | Languages | Considerations |
|---|---|---|
| Latin | EN, DE, FR, ES | Standard handling |
| Cyrillic | RU, UK, BG | Character encoding |
| CJK | ZH, JA, KO | No spaces, character count |
| Arabic | AR, FA, HE | Right-to-left |
| Indic | HI, BN, TA | Complex rendering |
Text Expansion/Contraction
| Direction | Typical Change | Example |
|---|---|---|
| EN → DE | +30% expansion | "Save" → "Speichern" |
| EN → ZH | -30% contraction | "Computer" → "电脑" |
| EN → FR | +15-20% expansion | "File" → "Fichier" |
| EN → JA | Variable | Depends on content |
Right-to-Left Languages
Arabic, Hebrew, Persian require:
- RTL text direction
- Mirrored UI layouts
- Bidirectional text handling
- Special punctuation rules
Language Quality Metrics
Source Quality Indicators
- Readability scores
- Terminology consistency
- Grammar/spelling accuracy
- Ambiguity detection
Target Quality Indicators
- Fluency assessment
- Accuracy verification
- Terminology compliance
- Locale appropriateness
FAQ
Why does language pair direction matter?
Different directions have different translation markets, rates, and quality expectations. Translating into your native language typically produces more natural results because you intuitively understand nuances, idioms, and cultural context.
What's the difference between zh-CN and zh-TW?
zh-CN is Simplified Chinese (used in mainland China, Singapore), while zh-TW is Traditional Chinese (used in Taiwan, Hong Kong, Macau). They differ in character forms, vocabulary, and some cultural references.
Should I use 2-letter or regional language codes?
For single-region projects, 2-letter codes (en, de, fr) work fine. For multi-region or locale-specific projects, use BCP 47 codes (en-US, en-GB) to ensure proper formatting and terminology.
How do I handle content with mixed languages?
CAT tools can mark inline foreign text differently. Best practice is to maintain the source language text in quotes or special markup, with translator notes for how to handle it.
What about machine translation for rare language pairs?
MT quality varies significantly by language pair. Major pairs (EN-ES, EN-ZH) have excellent MT. Rare pairs may have poor MT quality and require more human translation or post-editing effort.
How does text expansion affect localization?
Plan for expansion in UI design and layouts. Leave extra space for German (+30%), double-check layout after translation, and use responsive designs that accommodate varying text lengths.