I morgon bitti means 'tomorrow morning', but bitti is a little bit of language you'll rarely see anywhere else, so let's explore the history of the phrase.
Morgon in Swedish means 'morning'. And if you’ve been learning Swedish for a little while, you might know that adding the preposition i to a time noun can mean a few different things.
In some cases, it means you’re referring to a period of time that’s still continuing, or has just finished. If you say you’ve been waiting i en timme, it means ‘for an hour’, or if you’ve been living in Stockholm i tre år, you’ve been there for three years: these are completed periods of time, even if the action still ongoing (maybe you're still living in Sweden, but the three years are complete).
If you talk about something happening i natt, it can mean either tonight, overnight, or last night, depending on which tense you use. There's a bit more information on time prepositions in the article below:
But the phrase i morgon (literally: in the morning) always means ‘tomorrow’, talking about a period of time that hasn't yet begun. Before you tear up your Swedish grammar book, that’s not as counterintuitive as it sounds.
In older forms of English, people referred to things happening ‘on the morrow’, and now they say ‘tomorrow’: these words share their origin with Swedish morgon.
This left a gap in vocabulary: because morgon was already part of the phrase, how do you refer to something specifically happening tomorrow morning? One alternative would be to say something like 'på morgonen i morgon' (in the morning tomorrow), but that sounds a bit strange.
Here’s where bitti comes in. Bitti is a descendant of the word bittida, meaning ‘early’, used in Sweden since the 14th century and borrowed from Low German bi tide, which meant ‘in time’. Adding it to the phrase i morgon specified that you were referring specifically to the following morning, literally 'early tomorrow'.
Bitti, the shortened form, has been recorded in Swedish since the late 1700s, and today bittida has almost fallen out of use. Bitti is also rare, so you're likely to only really hear it within the phrase i morgon bitti.
Tågförseningar tills i morgon bitti
Train delays until tomorrow morning
Vi hörs imorgon bitti!
Speak to you in the morning!