。
Papa also had some grounding in Latin.
Literal
Papa [topic-は] Latin [genitive-の] grounding [also-も] had [explanatory-の] is.
A casual family reminiscence with a slightly elevated vocabulary choice. 素養 (そよう) is a register-marked word for 'grounding,' 'basic training,' 'the educated background someone brings to a subject' — a cultivated word, more literary than 知識 or 基礎. ~もあった ('also had') implies that other accomplishments or knowledge have already been mentioned — the Latin is being added to a list. The explanatory のです (its casual form なのです here contracted as のです) frames the whole utterance as a reveal or explanation, as if the speaker is lifting a curtain on something the listener didn't know.