When to use the single character vs double character form of a verb? I know of many verbs that can be expressed as a single character or two characters (i.e. 说 &amp; 说话). The issue is that I don't know when it is appropriate to use one of over the other. Is it dependent on the subsequent word? For example, "我吃米" and "我吃饭面包"? Or is it the other way around? Neither? Personal preference perhaps!? I've read that there is a natural tendency in Chinese to minimize the number of characters in compound words. That being the case, should I avoid using the two characters versions entirely?
I'll try answering this (but be aware I'm just a learner).

The given examples are transitive vs. intransitive verbs:


说 vs. 说话.  Here, 说 is a transitive verb (i.e., it takes an object) whereas 说话 is an intransitive verb (i.e., it doesn't take an object):


  他说“你好”
  He says hello
  
  你为什么那样说话？
  Why do you speak that way?


We can alternatively think of 话 (noun) as what is being said (说).
吃 vs. 吃饭.  Again, 吃 is a transitive verb whereas 吃饭 is an intransitive verb, so 我吃饭面包 is incorrect, but 我吃面包 is correct.

Again, we can alternatively think of 饭 as the object being eating (吃).


(I also note that both 说 and 吃 can be used as intransitive verbs, e.g., 你别说了 and 他什么都没吃.)

学 vs. 学习

Another example is 学 and 学习 which are both transitive verbs.  So both of these are grammatical:


  我学汉语。
  我学习汉语。


In this case, which do we choose?  See this question: What&#39;s the difference between 学 and 学习?  It's somewhat a matter of preference, circumstance, etc.