Learn Polish: Mój syn studiuje informatykę. - My son studies computer science.

In Polish, the verb studiować is strictly used for studying at a university or college level as a degree student. If the son were in primary school, high school, or just learning a skill on his own, you would use uczy się instead.

Why is the word for computer science spelled informatykę instead of informatyka?

The dictionary form is informatyka, which is a feminine noun. Because it is the direct object of the verb studiuje (it is the thing being studied), it takes the accusative case. For feminine nouns ending in -a, that ending changes to -ę in this case.

Does informatyka only mean computer science?

It translates to computer science as an academic subject, but it is also the general Polish word for IT (Information Technology) or computing. If someone works in IT, you would also use a form of this word, like working w informatyce.

Why doesn't mój syn take any special endings here?

Because mój syn (my son) is the subject performing the action, it stays in the nominative case, which is the basic dictionary form. It doesn't change its endings because it is not the object of the verb.