L1 Acquisition

After reading only a couple of chapters of Essential Linguistics by Freeman & Freeman (2004), I found this is a book that you feel easy to get into. Linguistic knowledge is explained in an interesting and lively way which immediately moved my fear of feeling bored when reading linguistics away.
As for the views of the first language (L1) acquisition, I think the insights from different researchers are valuable. L1 learning does relate to developmental psychology and the importance of environment. However, neither of the above theories could give us a full picture of how L1 is learned. That is why they were challenged by the theories of linguistics. Chomsky’s Generate Grammar indicates that many sentences may have a surface level and a deep level meaning, which is kind of similar to Finegan’s two of the three faces of language. I cannot help thinking if the meaning of a sentence or the way to express a meaning (active or passive) is situational. If a child just says something without any context, s/he could make it really ambiguous; while, if the sentence is said in a particular situation, would that be confusing as well? Universal Grammar (UG) always sounds too hard for me to believe. My question is: If there is a universal grammar for children to develop their L1, why would some children have much more difficulties in L1 learning than other children, even some of them have defect on this issue? Why would this built-in knowledge not seem helpful to them? Or maybe this is a question we need to ask cognitive psychologist?
Freeman & Freeman’s views of reading, writing and 2nd language (L2) learning reminded me of my own language learning experiences when I was young. I think I was taught to read in the way that word recognition view describes. Chinese pinyin system came first in my first grade’s Chinese language class; then we began to learn vocabularies and read aloud after the teacher or classmates or read by ourselves. Understanding a text was the last thing. Comparing to “sociopsycholinguistics view”, I certainly can see the drawbacks of the way I learned. However, I still think that reading aloud should be a part of learning to read, because I do not think silent reading can help develop our phonology skills as well as reading aloud, especially for beginners. I learned writing in a traditional way, too. I was curious about my current writing skills if I was taught in a process way. Maybe I could see that if I teach my future students through this method.
I guess it is known that traditional method in English teaching was quite popular in China. Actually, it still is in some areas. We had to do a lot of drills and exercise in our English learning. Imagine if more communicative activities were used in our classrooms, there would not be so many English learners are so struggling to improve their speaking skills, I think.
The last point I want to make here is about the Critical Period (CP) Hypothesis. On Page 41, it says: “Once past that period, people are not able to acquire a second language.” I was wondering if there is a bias here. I believe there are examples in our real life that people who past that period came to the US and they can still “acquire” English. It depends on how long and how much effort it takes. The CP might exist; however, a young child and an adult both have advantages in their L2 learning. These are just my thinking, though.