Learn Finnish: Aiemmin asuin lapsuudenkodissa. - Earlier I lived in my childhood home.

It comes from the word aikaisin (early). Aiemmin is the comparative form, meaning "earlier". While this lesson covers specific timeframes using postpositions like sitten (ago), aiemmin is a very common general adverb for saying "previously" or "in the past".

Why is there an 'n' in the middle of the word lapsuudenkodissa?

It is a compound word made of lapsuus (childhood) and koti (home). In Finnish, the first part of a compound word is often put into the genitive (possessive) case to link the concepts together. Lapsuus becomes lapsuuden, so the word literally translates to "childhood's home".

Why does koti change to kodi- in lapsuudenkodissa?

This is a quick reminder of consonant gradation. When we add the inessive ending -ssa (in) to koti, the final syllable becomes closed. This forces the strong consonant t to weaken into a d, resulting in kodissa.

Why isn't the word minä (I) used before asuin?

In standard Finnish, you can usually drop the subject pronouns for "I", "you", "we", and "you (plural)". The -n ending on the verb asuin already makes it perfectly clear that "I" am the one who lived there. Including minä would be grammatically correct but would add extra emphasis, sounding more like "I lived...".