Why is my native language so complicated?

As native English speakers, we generally don’t take the time to think about the way our language is put together. Even when I taught ESL in college, I mainly taught to native Spanish speakers, whose language is nearly as complex as ours. But now I teach English to people whose native language has NONE of the following: Verb tenses, verb conjugation, plurals. It also has few words. There are maybe 50,000 words in Khmer. There are over 200,000 in English. ‘More’and ‘Again’ are the same word in Khmer. As are maybe, possibly, approximately, around, about, roughly, and perhaps. Also questions are very difficult for them. In their language, they just add the word no to the end of a sentence. Thus, when I try to explain why an action that began in the past and is already completed takes a different tense that one began in the past but is still happening, I often rue the excessive complexities of English. While I appreciate the subtle differences that these can make in literature, they tend to make my everyday life just a little bit more difficult. You can't just translate a lot of English concepts simply because the concepts are entirely new to the students in any context. The usage of Khmer differs from English so much that often the students think I don't understand their questions or that I don't know my own language. For example, a girl asked about what a market vendor might say when he or she hadn't sold much. I told her that we would probably say that business has been slow or we hadn't done much business. She argued with me for nearly ten minutes because I hadn't translated it word for word into Khmer. I told her that we wouldn't say "me offer not sell" (the literal translation from khmer) Yes, the local language is a whole other animal. Here are some literal traslations of everyday conversations one may have in Khmer.

Host Grandma: Go market no? (Are you going to the market?)
Me: Go. (Yes, *responding with a verb is more common than saying the word yes)
HG: Take basket come (Bring the basket with you * the market basket serves the purpose of a shopping cart)

At the market:
Random person: Come from where? (Where are you coming from?)
Me: House.
RP: know wear sarong too. (You can wear a sarong! That’s fantastic!)

At the breakfast stall:
Breakfast lady: Niece eat what?
Me: Niece eat rice (people almost always refer to themselves and others in the third person, usually by some sort of kinship term.)
Random Person: White person know eat rice! (The foreigner is capable of consuming rice. Excellent)
RP: have age how many already? (How old are you?)
Me: I have age 23 already
RP: Take husband yet?
Me: not yet
RP: Want you take husband when? Want take husband cambodia?
Me: No want husband. Want work want study more.
RP: Have older younger how many person? (how many children do your parents have?)
Me: 2

At school:
Student: In Cambodia how teacher feel? (Do you like it here?)
Me: Teacher feel happy.
Student: sorry late last morning feed cow feed chicken. (I’m sorry I’m late, I had to feed the cows and chickens this morning)
Me No anything No. (That’s fine, I understand.)
Me: Younger younger remember what from yesterday? (What do you all remember from yesterday?)
Student: Teacher student remember small small (I don’t remember very much)
Me: Have person which other more remember anything? (Who remembers?)
Student: Teacher, I remember sentence have noun have verb one more (I remember a sentence needs a noun and a verb)
Me: Time all aldready! meeting each other day tomorrow (Time’s up! See you tomorrow)
Students: Goodbye teacher

I haven’t heard dance of the sugarplum fairies man for a while, so I will assume theme from Titanic man has prevailed!