Learn Swedish: Han lade nyckeln i väskan. - He put the key in the bag.

In Swedish, there is no single generic word for "put". You have to choose a verb based on how the object is positioned. Because a key is generally laid down flat or dropped into a container, we use lägga (to lay/place horizontally). Lade is its past tense. If you were putting an object in a standing position, you would use ställa instead.

I often hear Swedes say la for "put". Is that the same as lade?

Yes! Lade is the correct standard and written past tense of lägga, but in everyday spoken Swedish, it is almost always shortened to la. You will often see la written in casual texts or chats, too. Saying Han la nyckeln i väskan is perfectly natural.

The dictionary form of "key" is nyckel. Why is "the key" spelled nyckeln instead of nyckelen?

When an en-word ends in -el, -er, or -en (like nyckel or cykel), it drops its final e before you add the ending that means "the". This rule exists to make the word easier to pronounce, giving us nyckeln instead of the clunky-sounding nyckelen.