Swahili Noun Classes Make My Head Hurt

Each Swahili noun belongs to a class. The class the noun belongs to determines how to form it's adjectives, demonstratives, verbs, modifiers... I think I can make myself understood when speaking Swahili without knowing the noun classes, but I can't understand a person who uses noun classes correctly when speaking to me unless I also know the noun classes.

Here's an example I saw on Dana Hooshmand's page that illustrates my point. 

Swahili		English
Kitu kizuri ambacho kipa hapa.		The nice thing that is here.
Gari nzuri ambalo lipa hapa.		The nice car that is here.

Everything in red changes from the first Swahili sentence to the next based on the noun classes of Kitu (thing) and Gari (car), yet only one word changes from the first English sentence to the next.

I copied the chart below from something Dana Hooshmand posted to try to help me keep up with Swahili noun classes. When I wrote this post, the sheet was available as a .pdf.

I have a hard copy of the chart and use it to work through translating my English into Swahili. If I can't remember which class a noun belongs to, I refer to Noun Classes section of Kiswahili Lessons at The University of Kansas website. Here's how I work through my translations.

English Sentence	Noun Class	Swahili Sentence
These are the people that wrote	People= Watu M/Wa Class	Hawa ni watu waliandika
This motorcycle is broken.	Motorcycle= Pikipiki N Class	Pikipiki hii haifanya kazi
My dog's name is Hank.	Dog=Mbwa M/Wa Class Name=Jina Ji/Ma Class	Jina la mbwa wangu ni Hank.

Below, I'm building on an exercise I found on the University of Wisconsin website that also helps me with noun classes.

Class	English	Swahili
M	The child of mother grew.	Mtoto wa mama alikua.
Wa	The children of mother grew.	Watoto wa mama walikua.
M	The tree of mother grew.	Mti wa mama ulikua.
Mi	The trees of mother grew.	Miti ya mama ilikua.
Ji	The fruit of mother grew.	Tunda ya mama lilikua.
Ma	The fruits of mother grew.	Matunda ya mama yalikua.
Ki	The island of mother grew.	Kisiwa cha mama kilikua.
Vi	The islands of mother grew.	Visiwa vya mama vilikua.
N	The banana of mother grew.	Ndizi ya mama ilikua.
N	The bananas of mother grew.	Ndizi za mama zilikua.
U	The rib of mother grew.	Ubavu wa mama ulikua.
U	The ribs of mother grew.	Mbavu za mama zilikua.