Which written language has the least number of letters?

It's tricky to say definitively which language has the absolute fewest letters, as there are different ways to define "letters" and "language". However, here are some contenders:

* Rōmaji (Japanese) - Uses only the 26 letters of the English alphabet to represent Japanese sounds. This is a system for writing Japanese using Latin script, not a true alphabet.

* Hawaiian - Has only 12 letters: A, E, I, O, U, H, K, L, M, N, P, and W. However, these letters represent a larger number of sounds.

* The International Phonetic Alphabet (IPA) - Has 107 symbols that represent sounds in spoken language, not written language.

Ultimately, it depends on how you define "language" and "letters". If you're looking for the language with the fewest *unique* symbols in its writing system, Hawaiian is a strong contender.