I think there is a problem of terminology here:
Training time is the result of training size and training speed and is the time that it takes for your barracks to produce the units in the queue.
Most likely your are talking about training speed though? Well the speed depends on only 2 things: The level of your troops producing building and the level of speed increasing AW that goes with the building.
Training speed is exactly the same for all units (except for rounding errors), even though the numbers look different. That is because not all units have the same weight or size. Some units like Archers are size 1, while others are size 6 (like treants). So the training size for 1 unit is 6 times as long. But you need 6 times as many Archers to form 1 squad. So producing1 squad of units takes exactly the same amount of time. The game always uses squads of units, never individual units or certain numbers of units. So this whole thing is completely unimportant for game play. So to make it easy for yourself always look at size 1 units.
This is why in the link above you have 12 minutes training time for size 1 units and 1h 12min (=6x12min) for size 6 units. It is as I have said completely useless information.
The number given in your troop production building as speed is a bit of a strange number, here the 12 comes back: the speed given is the number of units (of size 1) that you can produce in 12 minutes. Don´t ask my why.