Many children between ages 7 and 11 excel at switching formal informal forms of language?

It's true that children between ages 7 and 11 are often in a stage where they're developing their understanding and use of formal and informal language. However, saying they "excel" at switching between them is a bit strong. Here's why:

* Developing skill: This age group is still learning the nuances of different language registers. They might not always be *consciously* switching between formal and informal language, but rather are picking up on the cues from their environment.

* Context-dependent: Their ability to switch will depend heavily on the context. They'll likely use formal language when talking to adults or in more formal situations like school, but revert to informal language with friends or family.

* Gradual process: Learning to use language appropriately in different situations is a gradual process that continues throughout childhood and adolescence.

So, while children in this age range are *developing* this skill, they may not be "excelling" at it yet. They are more likely to be experimenting with different registers and learning by trial and error.