AEIOU

The 5 vowels of Hiragana.

あ a - 'ah'
い i- 'ee'
う u - 'oo'
え e - 'eh'
お o - 'oh'

The rest of the Hiragana have to use a,i,u,e,o. For example, the 'S' of the Hiragana:

さ sa し shi す su せ se そ so

With this, we can form おいしい. This translate into oishii - delicious/enjoyable (food/drinks).

Tada~

Sushi - すし

Welcome to the 'S' series of the Hiragana. Hiragana is 1 of the 3 Japanese writing systems. 

さ sa 
し shi 
す su 
せ se 
そ so 

Taking su and shi, you will get すし = sushi.