I think he wanted to show his command of the language off to himself.

However, his command of the language is far above average.

He had a perfect command of the French language and culture.

If so, does this person have complete command of the English language?

He was struck again by her command of the language.

He was very impressed with your son's command of the language.

"Come see," she said, but her command of the language was still very basic.

It might have been a weakness in his command of the language, but she did not think so.

However, she was criticized for her command of the Chinese language.

"His command of the language is strong, often without an accent."