Breakdown of Trzeba wezwać hydraulika, chyba że sam to naprawisz.
to
this
sam
alone / himself (emphatic) / pure / nothing but
trzeba
one must, it is necessary (+ infinitive)
naprawić
to fix (perfective)
Questions & Answers about Trzeba wezwać hydraulika, chyba że sam to naprawisz.
Why does chyba że mean "unless" when chyba usually means "probably"?
You're right that on its own, chyba usually means "probably" or "I guess". However, when combined with że (that), it forms the fixed conjunction chyba że, which always translates to "unless". It introduces a condition that would change the situation in the first part of the sentence.
The English translation says "unless you fix it" (present tense), but isn't naprawisz the future tense?
Yes, naprawisz is in the future tense because it's a perfective verb (indicating a completed action). In English, we often use the present tense after "unless", but Polish is more strictly logical about time: the fixing hasn't happened yet, so it uses the future tense to show it's a condition for the future.
Why is the plumber hydraulika with an "-a" at the end instead of just hydraulik?
Because the plumber is the direct object of the verb wezwać (to call), so it takes the accusative case. For masculine animate nouns (people and animals), the accusative case looks exactly like the genitive case, which is why it gets the -a ending here.
Could I say musimy wezwać instead of trzeba wezwać?