Yoruba has 25 letters in its alphabet.

They are:

A B D E Ẹ F G GB H I J K L M N O Ọ P R S Ṣ T U W Y  (Upper case)

a b d e ẹ f g gb h i j k l m n o ọ p r s ṣ t u w y (Lower case)

The vowels are a bit more involved, though, because in the language, the sound determines the meaning. That's why it is called a tonal language.

Yoruba vowels are

a = à á

e = ẹ é ẹ́ ẹ̀ è é

o = ọ ó ọ́ ọ̀ ọ ò

u = ù ú

i = í ì

So, you do not have to wonder how a word is pronounced once you see it spelt right. For instance, it isn't actually Yoruba but Yorùbá.

That's all for now.

 Yoruba tone marks on vowels