Are you playing combat out on a map or battle map with dioramas and tracking movement rates in detail? I run DnD strictly theater of the mind and distances and range are approximated. Combat in B/X is ten seconds. It easy to get agreement on what a person can do in that time frame. If I remember correctly AD&D is a 60 second combat round? To me this really fucks everything up. A combat round 6x longer than it should be creates too many concurrent actions to be adjudicated fairly and increases the amount of debate at the table. I turn to Richtofen's War from Avalon Hill as a good example of this. The turn is ten seconds and creates a broken game. You cut a turn down to 5 seconds and use that as the yardstick to figure out what that means with every other factor in the game and it plays better. Not awesome, but not nearly as ridiculous as the defined turn lenght.
In D&D?
It depends on the situation.
Typically, I usually do what I would call "assisted theater of the mind." That means that it's largely theater of the mind, but I may sketch some things out and use a few minis to illustrate the general idea of the situation.
Are you playing combat out on a map or battle map with dioramas and tracking movement rates in detail? I run DnD strictly theater of the mind and distances and range are approximated. Combat in B/X is ten seconds. It easy to get agreement on what a person can do in that time frame. If I remember correctly AD&D is a 60 second combat round? To me this really flargins everything up. A combat round 6x longer than it should be creates too many concurrent actions to be adjudicated fairly and increases the amount of debate at the table. I turn to Richtofen's War from Avalon Hill as a good example of this. The turn is ten seconds and creates a broken game. You cut a turn down to 5 seconds and use that as the yardstick to figure out what that means with every other factor in the game and it plays better. Not awesome, but not nearly as ridiculous as the defined turn lenght.
Language, please.
It varies.
For D&D, I typically do what I'd call "assisted theater of the mind" for a lit of things. I describe things and use a few sketches or minis to represent the general idea of where things are.
Star Wars Edge of the Empire handles things in a similar manner. That is where I got some ideas from, but what I do typically offers a little bit more nuance than the range bands from that game.
If an encounter is more complex or it seems that the players need more detail, I'll adjust the level of detail accordingly. If counting squares, my preference is to dispense with squares and just use the scale of 1 inch = 5ft. Though, I'm aware that breaking away from the square grid can be a tough transition for D&D players, so that's another area where I adjust to fit the group.
As a player, the D&D groups I game with tend to use a grid and minis. There's some article room though.
At Adventurer's League, a grid is used and things tend to be more strict in terms of counting squares and such.
I haven't perceived that using a grid or the amount of in-game time represented by the rules are primary factors involved in speed. I do notice that some players seem to pick up some level of anxiety when looking at a grid and I think that does contribute, but not moreso than other factors.
•D&D has 6-second turns.
•FFG Star Wars has.... honestly, I'm not sure; it depends on the scene being played out.
•GURPS has 1-second rounds as a default (but I tend to do car chases and such using a different time frame).
Those are the games that I currently play most frequently. Other games I've played have varying amounts of time represented by turns.