Translation:You are drinking water, she is drinking beer.
Verb roots never change (with 3 exceptions: etmek/tatmak/gitmek).
Even then, there are many nouns that keep the original -ç after adding suffixes that begin with a vowel. You mostly have to memorize them (but the majority of exceptions are single syllable words)
Turkish: Verb roots never change (with 3 exceptions)...
English: 'I' before 'e' except after 'c'. BUUUUUUUT, SOMEtimes... (a long list of words...)
This is why I love Turkish!