Learn Polish: Dziecko długo spało. - The child slept for a long time.

In the Polish past tense, the verb must match the gender of the subject. The subject here is dziecko (child), which is a neuter noun because it ends in -o. The -ło ending on the verb is the regular past tense ending for neuter, third-person subjects (like 'it').

How is the past tense form spało made from the dictionary form?

The dictionary form (infinitive) is spać (to sleep). To make the past tense, you drop the -ć to get the stem spa-, and then add the correct past tense ending. Since dziecko is neuter, we add -ło, making it spało.

Why do we use długo here instead of długi?

Długo is an adverb that means 'for a long time.' We use it here because it describes the action of the verb (how long the child slept). Długi is an adjective that means 'long' (like a long movie or a long road) and is only used to describe nouns.

Can I change the word order and say Dziecko spało długo?

Yes, you absolutely can! Polish word order is flexible. Dziecko spało długo is perfectly natural. Putting długo before the verb, as in this sentence, just puts a tiny bit more focus on the fact that the sleep lasted a long time.