There are some spelling variations, the people who made this course are Tanzanian, and have slightly different spellings than those people who are in Kenya or any other Swahili speaking country. For example, I've seen Ninyi spelled Nyinyi, knowing both helps even if you are only going to use one to lower the chance of confusion while you're talking to a Swahili speaker.
Hey! I decided to check some books, now that I got wi-fi, and I think I found out on the internet, after I checked Teach Yourself Swahili, apparently based in Tanzanian Swahili, and the spelling was the same.
- embe/maembe: mango(es)
- mwembe/miembe: mango tree(s)
- parachichi/maparachichi: avocado(s)
- mparachichi/miparachichi: avocado tree(s).
So, apparently, changing the noun class of a fruit from ∅/ma to m/mi gives us the tree.