lettertosound

Letterto sound, also referred to as letter-to-sound mapping or grapheme-to-phoneme conversion (G2P), is the process of converting written letters into spoken sounds. It describes how orthographic symbols or graphemes correspond to phonemes, the distinct units of sound in a language. The term is used in linguistics, speech technology, and literacy education to discuss how spelling relates to pronunciation.

In practice, lettertosound can be realized as a set of rules, statistical models, or neural networks that take an orthographic string as input and produce a sequence of phonemes or phonetic representations. Some languages have relatively transparent mappings, where most graphemes have consistent sounds, while others, such as English, exhibit irregularities and context-dependent pronunciations.

Applications include text-to-speech synthesis, where accurate letter-to-sound conversion is essential for natural sounding voice, and grapheme-to-phoneme systems used in pronunciation dictionaries, spelling checkers, reading aids, and language learning tools.

Common approaches range from hand-crafted rule systems to data-driven models, including sequence-to-sequence and probabilistic G2P methods. Evaluation often uses phoneme-level accuracy, pronunciation dictionaries, and task-based metrics such as speech recognition or intelligibility tests.

Challenges include language diversity, non-Latin scripts, homographs, digraphs and trigraphs, and historical spelling changes. Multi-language and transliteration contexts may require language-specific rules or multilingual models.

See also: Grapheme-phoneme correspondence; phonology; orthography; text-to-speech; grapheme-to-phoneme conversion; dyslexia research.