Learn Swedish: Åk rakt fram. - Go straight ahead.

This is a command (the imperative mood), telling someone what to do. In Swedish, you make a command by using the verb's stem. For most verbs ending in -a, you just drop that -a. So the infinitive åka (to go/travel) becomes the command åk (go!).

Could I say gå rakt fram instead?

Yes, but it changes the meaning slightly depending on how the person is traveling. Åk specifically means to go using a vehicle (like a car, bike, or bus). If you are giving walking directions, you would tell them to walk by using the command form of gå, which is just gå rakt fram.

Why does rakt have a -t at the end?

The base word is the adjective rak (straight). Because it is describing an action here (how to go) rather than a noun, it acts as an adverb. In Swedish, you often turn an adjective into an adverb by adding a -t, similar to adding "-ly" in English.

I've seen the word framme before. Why is it fram here?

Fram implies motion or direction (forward/ahead), which fits perfectly with an action like åk (go). Framme is used when there is no longer any motion, meaning you have arrived or are already at the destination (for example, vi är framme means "we are here" or "we have arrived").