Questions & Answers about Moj propali projekt je pun pogrešaka.
propali looks like a past tense verb. How is it being used here?
propali is the active past participle of the verb propasti (to fail). While usually used to form the past tense, here it functions completely as an adjective. It directly modifies projekt to mean a project that has already failed (a "failed project").
If the masculine singular participle for "to fail" is propao, why is it propali here?
When acting as an attributive adjective placed directly before the noun, it uses the definite adjective ending -i. Adding this suffix to the base participle changes the final -o back into its original -l-, transforming propao into propali. If it were used as a past tense verb instead, you would say projekt je propao (the project failed).
Why is the word for mistakes, pogrešaka, in the genitive case?
The adjective pun (full) always requires the noun that follows it to take the genitive case, similar to the English "full of". Because there are multiple mistakes, pogrešaka is in the genitive plural.
The basic noun is pogreška. Where does the extra 'a' in pogrešaka come from?
This is an instance of the "fleeting a" (nepostojano a). In the genitive plural, Croatian frequently inserts an a between the final two consonants of a noun's stem to make pronunciation easier. Here, it breaks up the -šk- cluster, resulting in pogrešaka.