Learn Swedish: Pojken lekte i parken. - The boy played in the park.

Lekte comes from the verb leka (to play). It belongs to a regular group of verbs whose root ends in a voiceless consonant sound, specifically p, t, k, or s. Because the root lek- ends in a k, the past tense ending becomes -te instead of -de. This simply makes the word easier to pronounce!

Could I use spelade instead of lekte to say 'played' here?

No, because Swedish has two different words for playing that are often mixed up. Leka (past tense: lekte) is used for imaginative, unstructured play, like children playing in a park. Spela (past tense: spelade) is strictly used when playing structured games, sports, board games, or musical instruments.

Why do both pojken and parken end in -en?

That -en ending is a refresher on the Swedish way of saying 'the'. Both pojke (boy) and park (park) are en-words. To make them definite ('the boy' and 'the park'), you attach -n or -en to the end of the noun instead of putting a separate word in front of it.

If the sentence was about multiple boys, would the verb change?