Could you tell me if there is any difference between sound someone out and feel someone out? For example:
I'll try to sound the boss out to see if he'll give us a pay rise.
I'll try to feel the boss out to see if he'll give us a pay rise.
Generally, to sound out someone means to directly ask them questions to discover their intentions - "Boss, are we getting a pay rise?" Think of it as encouraging someone to sound their answer out loud. https://www.merriam-webster.com/dictionary/sound%20out
To feel someone out is usually more indirect; you'd dance around the issue at hand without directly asking them. "So, boss, any changes we should know of coming up?" Think of it as slowly feeling your way towards an answer in the dark. https://www.merriam-webster.com/dictionary/feel%20out