Learn Turkish: Yeni makine sadece kullanışlı değil, aynı zamanda zahmetsiz. - The new machine is not only practical, but also effortless.

The pattern is sadece ... değil, aynı zamanda .... Literally, this translates to 'only ... not, at the same time ...'. The word değil (not) follows the first adjective kullanışlı (practical) to mean 'not only practical', while aynı zamanda introduces the second adjective zahmetsiz (effortless).

The lesson mentions the structure 'sadece ... değil, aynı zamanda ... (da)'. Why is there no da or de at the end of this sentence?

The additive particle da/de (meaning 'also' or 'too') is optional in this structure. You could say aynı zamanda zahmetsiz de at the very end, but leaving it out is incredibly common and sounds perfectly natural, especially when connecting two simple adjectives.

How is the word kullanışlı (practical) formed?

It is built from the verb root kullan- (to use). Adding the suffix -ış turns it into the noun kullanış (usage or manner of using). Finally, adding -lı (meaning 'with' or 'having') makes it an adjective. So, a machine with good usage is kullanışlı (practical or useful).

Is the suffix -siz in zahmetsiz the same as the English suffix '-less'?

Exactly! The noun zahmet means 'trouble', 'bother', or 'effort'. The suffix -siz (which changes vowels to match the word) means 'without'. Therefore, zahmetsiz literally translates to 'effortless' or 'trouble-free'.