I think the trainers were just unable to train many commands

I think you can use too many words, we do like to chatter to our dogs. But dogs can have quite a big vocab for individual commands

as long as each one is fully trained

and you remember the words you are using (I made a spreadsheet)

None of mine have shown any signs of being confused because they've been taught more than a handful of commands. How many did these trainers consider too many?

Ditto

The first trainer asked me to write them down and I seem to remember there were about twenty. It was a few years ago.

The next time it happened was with a gundog trainer who seemed to think more than two commands would be confusing. Mind you he used a whistle.

And I definitely don't mean several commands for the same thing. Although I solved a problem with my shepherd by using 'straight' for a formal recall instead of 'come'. She then understood that she had to come into the present position and not just come and sit any old way (which was acceptable to me as a response when we were out and about).

20 commands doesn't seem excessive to me to be honest. Rupert probably has that many behaviours on command and we're working on several more. As long as you've taken the time to make it clear what each command is why should the dog be confused?

As for 2 different commands for the recalls, well I'd think it'd be more confusing for the dog for a command to sometimes mean come to me and sit wherever and sometimes mean come to me and sit exactly here as soon as you reach me. To me it makes sense to have one command for a chilled out recall and another for a formal obedience one as they're not the exact same behaviour.

To me it makes sense to have one command for a chilled out recall and another for a formal obedience one as they're not the exact same behaviour.

Ditto

Although an obedience trainer said she uses the same command and just stands differently.

I used to use the same command for both recalls with my last goldie and she understood the difference. Maybe it was the position of my hands and the context in which the command was given (the setting up, walking away etc).

I think it depends on the dog. Shamus struggles with more than 3 (come, sit, gerroff ) but Daisy soaks up training and loves to learn.

Which in itself changes the command

Yes that's true. But Tala didn't realise she was supposed to respond differently with different body language yet when the command word was changed a light went on

Alfie knows a fair few commands and never seems confused.
He picks things up super fast though, and picks up on human language (if I am just chatting to him, I have noticed he knows what some of it means - for example he knows "give" means put it down, leave it means to leave it alone and walk away, or to drop a toy and leave it where it is, and in my chatting I have obviously said "no no you can't take that outside put it down", and then said leave it/give etc, and just a week or two ago i have noticed if i say "put it down" he does so.... that was not taught ). Plus, mum constantly uses the wrong words for commands, but he always knows which one she means.. she can use a word he doesn't even know and he always knows what she means too - never seems confused!

I think it possibly depends on the dog? But Alfie knows a lot and doesn't get confused