It was fun to contribute with a quiz on linguistic diversity in the world and in the Greater Malmö area for the daily newspaper Sydsvenskan (2021-10-09).
The database Ethnologue is an excellent source for general data on the topic. Data on the linguistic diversity of Malmö is harder to get, as Sweden does not have census statistics on languages spoken in the country. I used school statistics on the pupils’ mother tongues to get a picture of the linguistic diversity in the the Greater Malmö area. I wrote a paper on this a couple of years ago, that I used here: Malmös språkliga landskap (in Swedish; The linguistic landscape of Malmö).