Ma me tchi
When written in Romaji, each letter has the same pronounciation in every occurance. (Unlike English where the pronounciation of letters depends on their location in a word, and other letters on either side of them.)
A: is pronounced the same as the each a in banana.
I: is the same as the i in ski (down-hill sport on snow).
U: is similar to, but not quite as long as, the double o sound in moon.
E: is as the e in net.
O: as in no (opposite of yes).
G: as in go.
Y: as in yellow.
Most Japanese characters consist of a consonant sound and vowel sound together (such as "ma", "me", "tchi".) The only exceptions are the vowels "a", "i", "u", "e", and "o", which can be alone, and the consonant "n" can be alone (as in "pa" "n" "da".)
The i on the end of "shi", "chi", and "tchi" when occurring at the very end of a Japanese word, is sometimes silent, in casual conversation.
Note: Bandai has embeded English words in some Tamagotchi character names. You can't use the Romaji rules of pronounciation for these names. Example: Maidtchi is English "Maid" and Japanese "tchi"