What kind of cock-a-mamie language is this anyway

My friend keeps trying to teach me more Chinese.

Last week I learned a word for "potato" -  tu(3) dou(4)*.

The individual syllables for this mean, respectively, "earth" and "bean". It's a bit of a stretch but no more so than French's "apple of the earth" - pomme de terre.

This week I learned there is another word for "potato" - ma(3) ling(2) shu{3)*.

The individual syllables (as spoken, not written) mean "horse" "zero" "mouse".

Horse zero mouse?

Horse zero mouse?

Horse zero mouse?

In what kind of language does horse zero mouse = potato? 

I'll never get to grips with this. Think I'll get someone to send me out my Klingon dictionary. It's easier.

*If you're wondering about the numbers they show the correct tones for the syllables.