Translate text between 100+ languages. Max 500 characters per call. Returns translated_text and confidence (0-1). Set target_lang to IETF code: 'de' (German), 'fr' (French), 'es' (Spanish), 'ja' (Japanese), 'zh-CN' (Chinese Simplified), 'ar' (Arabic), 'pt' (Portuguese), 'it' (Italian), 'nl' (Dutch). source_lang defaults to auto-detect.