Translation:Chai ya maziwa
Maybe to make the distinction? I don't know, but it is a common mistake among learners to assume that chai and chapati are in the ki-/vi- class, and it may be good to get exposed to this early on. Maybe they want you to discover this exact point, that not all nouns starting in ch- or ki- are in the ki-/vi- class.
Good to know I am not alone, vtopphol, and I admire your generous interpretation that they planned this carefully. However, I think I would learn that point better with chai in the N/N lesson (which comes afterwards and is where it belongs). At least this discussion makes sure I won't forget chai and chapati.
I have noticed that several sections include commonly-confused words, and I greatly appreciate that the creators of this class have made efforts to do this. I think it greatly helps me learn and understand the language better. I don't think that vtopphols interpretation is overly generous at all. In fact research on learning has shown that while students feel that they learn better by studying one topic at a time, they actually benefit more from an interweaving method such as that included here.
Many do, but not all of them. Chai and chapati are two notable exceptions. Many of them are of foreign origin. Most foreign words go into two noun classes. The i-/zi- class is the most important, and nowadays most loanwords go into this one, but historically the ma- class (or ji-/ma-) was often used. Even today loanwords that are descriptive of people will often be placed in this category in order to show animacy.
maziwa (ma class, plural only)
2) plural of ziwa (breasts; lakes)
(So, I think we only use the plural form "maziwa" for milk, breasts and lakes)
ziwa (ma class, plural maziwa)
1) lake (body of water)
2) breast (organ)
Yes, "chai na maziwa" is tea with milk, or possibly tea and milk. But the sentence given here is "chai ya maziwa" which is slightly different. "Milk tea" is the most precise. I can accept "tea with milk" if by that you mean tea made almost entirely out of a base of milk, with only very little water.