Language/Lingala/Grammar/Prepositions
As you’ll have noticed above, Lingala uses one or two key prepositions – na (nah) and ya (yah) – in almost every sentence. These two little words are often indispensable in connecting the various parts and you’ll often see more than one in any given sentence, although at first it might not be entirely apparent why.
It can also be a little confusing, because na can sometimes seem to have the same meaning as ya, but it doesn’t really seem to work the other way around.
The definitions of these two important little binders are:
na – and, on, in, of
ya – of
In Kinshasa, they are basically interchangeable, but in other parts of the country there is a clear distinction between the two. Most of the people you will likely hear talking in Kinshasa will be using na a lot more than ya, so don’t let it throw you. And don’t get too hung up about which one to use, especially when you’re just starting out. Plenty of time to practice the finer points later on. When you’re first starting, if in doubt, add a na and you probably won’t be far off the mark.
Source
https://lobalingala.files.wordpress.com/2014/07/23042014-loba-lingala.pdf