Breakdown of Onlarla birlikte parkta yürüyoruz.
onlar
they
park
park
yürümek
to walk
ile
with / by / and (linking nouns)
Questions & Answers about Onlarla birlikte parkta yürüyoruz.
How do we get onlarla from onlar (they)?
The postposition ile (with) is usually attached directly to the preceding word as a suffix. Following vowel harmony, it becomes either -la or -le. Since onlar ends in a consonant and has an a in its last syllable, we add -la to make onlarla (with them).
Why do we use both -la (with) and birlikte (together)? Isn't that repetitive?
In English, "together with them" might sound a bit redundant, but in Turkish, pairing the ile / -(y)la suffix with the word birlikte is incredibly common. It strongly emphasizes doing the action as a group. You could drop birlikte and just say Onlarla parkta yürüyoruz, but keeping it sounds very natural.
Why is the word for "in the park" parkta instead of parkda?
This is because of consonant harmony! The word park ends in a hard, voiceless consonant (k). When we add the location suffix -da (in/at/on), the d changes into a hard t to match the k, giving us parkta.
Where is the word for "we" (biz) in this sentence?