The ability to learn language is a quality of the human species because humans obviously are not designed to acquire one language over another.
this is evident in the fact that not one language is a dominate language in the world and that many people can be bilingual, trilingual, etc.
for example, the English word ball references the idea of a round object that has certain properties of rolling and bouncing and that is often used in a game or other physical activity.
I think that developing semantic knowledge and semantic networks is important in child development because it allows them to classify items that are uncertain to them. I also believe that parents should play a key role in Semantic Knowledge by correcting their child when they classify objects that look the same into one category (when they are not the same). For example, lion is different then a tiger.
Expressive language refers lo a child's production of language lo communicate. This develops orally first during social interactions and as a child's speech mechanisms mature allowing the child to gain control over producing specific speech sounds.
when i think of expressive language i think of children making noise when they are hungry, when they want a toy, etc. This along with hand movements indicate what the child wants.