This is kind of difficult to answer as languages vary a lot over time. Ethnologue keeps the account of how many languages are spoken in the world, they state that they are in flux, they modify depending on the context. In their 2009 list, there were 6,909 different languages, today they list 7,111. So the option of between 5,000 and 6,000 is the one closer if we asume the number of languages increased over time and the list was done between 2009 and 2019. The most spoken language is Mandarin, followed by Spanish.
