tone down

[Maybo]

Can I use "tone down" if someone switches to an simpler language from an advanced language?

For example: When John talks to children, he would tone down his language.

 

[Rover_KE]

To me, that means John is careful not to use any swear words when he talks to children.

 

[emsr2d2]

No. "Tone down your language" means "Don't swear as much".

When John talks to children, he simplifies his language.

 

[teechar]

Note that "tone down" works in other contexts and has a broader meaning.

Also, "an simpler" is ungrammatical, and "an advanced language" is wrong. You should not use the indefinite article with both instances of "language" in the above. "Language" in that sense is not countable.

https://www.lexico.com/definition/tone_down
https://www.lexico.com/definition/language

 

[Charlie Bernstein]

. . . When John talks to children, he simplifies his language.

To tone something down is to make it quieter, calmer, less aggressive.

If he avoids swearing around children, as some of the posts above have mentioned, we would say he cleans up his language.