Some Chinese examples for fun (hoping HN supports Unicode)...
To make something plural, you just add 们. I/me is 我, so we/us is 我们. He/him is 他, so they/them is 他们. No need for separate base words - learn the normal nouns/pronouns and one particle and you're done.
Same concept for possessive, you just add 的. Using the above, my is 我的. His is 他的. Their is 他们的. Easy.
Want past tense? Don't mess with the base words; again just add a particle, in this case 了. Go is 去 so went is 去了. Eat is 吃 so ate is 吃了. Easy. Learn the verb once and it never changes.
Forms of "to be" are similarly simple - the base words again don't change, you just add the "to be" word you want and get on with your life. Want to say "I am American"? America = 美国 and person is 人, so American is literally "America person" 美国人. Am for non-adjectives is 是. "I am American" = 我是美国人. "We are American" = 我们是美国人. Easy. Compare this to something like Italian, where "I am American" = Sono americano, but "We are American" = Noi siamo americani. Absurd in comparison.