Language Detector

franc uses trigram frequency analysis to identify languages. A trigram is a sequence of three consecutive characters — for example, the English word "the" contains the trigrams "th" and "he". Every language has a unique distribution of trigrams. English has frequent trigrams like "the", "ing", and "tion". Arabic has frequent trigrams involving common letter combinations in Arabic script. franc compares the trigram frequencies in your text against profiles for 187 languages and ranks them by similarity. This statistical approach is fast (no neural network needed), lightweight (no model download), and surprisingly accurate for texts longer than 20-30 characters.

Language detection is useful in many workflows. Content moderators use it to route user-generated content to the correct review team. Translators identify the source language before starting work. Customer support teams detect the language of incoming messages to assign the right agent. Researchers analyzing multilingual datasets tag documents by language automatically. Email marketers verify that content matches the target audience language. Developers building multilingual applications test that language routing works correctly. Because this tool runs locally, it is especially suited for sensitive text — legal documents, private messages, medical records, or proprietary content that should never be sent to third-party APIs.