Learn Dutch: We wonen in een klein huis. - We live in a small house.

Because the subject is we (we). In Dutch, all plural subjects (we, you plural, they) use the full infinitive form of the verb, which usually ends in -en. The shorter stem form woon is only used for singular subjects like ik (I).

If the full verb is wonen, why is the ik-form spelled with two O's (woon)?

This is because of Dutch spelling rules about vowel length. In wonen, the O is long because it ends a syllable (wo-nen). When we make the stem (the ik-form), we drop the -en. To keep that same long O sound before the final consonant N, we must double the vowel to make woon.

Why is the word for small klein here instead of kleine?

Most adjectives in Dutch get an extra -e at the end. However, huis is a het-word (het huis). When a het-word is used with the word een (a), the adjective in front of it does not get the -e. That is why it is een klein huis and not een kleine huis.

Can I use wij instead of we in this sentence?