Calling pitches for 11 YO s

Have the catcher & pitcher work together. The pitcher should feel free to shake off the catcher.

As far as pitches, your pitchers (especially at 11YO) should have more than just one fastball and a changeup. They should use the same fastball mechanics for every pitch, but should use a variety of grips.

At a minimum, they should be throwing four seam and two seam fastballs. And ditto for the seam orientation in their changeups.

Following is some info on grips that can be added fairly easily. There is nothing wrong with introducing different fastball and changeup grips. And the different movements and speeds will add weapons to their arsenal.

The modified circle change is similar to a true circle change, but instead of curling the forefinger all the way back into the web of the thumb, the tip of the forefinger is left touching the tip of the thumb. From the side it would look like the "ok" sign. Curling the forefinger all the way in creates undue stress in the tendons.
Some kids will get a great deal of movement by using various grips (two seam orientation, four seam orientation, two seam orientation but off center, etc.) with the modified circle. Hand size is not the determining factor in gaining control of the modified circle. Some of my kids with smaller hands have mastered this pitch well before kids with big hands.

The three finger change is a three finger grip with the thumb and little finger moved around to the side of the ball instead of being at the bottom. The ball is still held more in the fingers rather than being pushed back into the palm like a palm ball.
When they get older, the palm ball will not be a good option. To get the proper speed on the ball with a palmball, they will have to overthrow. This is due to the shortening of the lever (distance from wrist to the ball's center). If they don't overthrow, the change will be too slow compared to their fastball & it will be detected.
Some kids get more movement from the three finger. It can be throw from a two or four seam orienation.

They should use both changeup grips. They will probably get one down before the other, maybe a long time before the other. Whichever comes first, start using in the games. Then add the other as it is ready.

They can throw an intermediate changeup as well. Take a four seam fastball grip. Insteand of having the fore finger and middle finger together, move them apart (in a "V" shape) about an inch. No more than is comfortable. This is not a forkball, as the fingers stay on top of the ball. But widening the fingers will take ~ 5-7 mph off the pitch. Throwing this grip angled up & in on the batter's hands will almost always result in a foul ball.

Have them use their changeup grips every time they throw warming up. This will make a big difference in how quickly they gain control of their changeup. You must emphasize to them that NOTHING changes when they throw their changeup but the grip. They must keep their arm velocity up & their mechanics identical to their fastballs.

Now for some other fastball grips. Take a two seam grip & rotate it 90 degrees until the fingers are across the seams instead of with the seams. This pitch will normally tail outside. This is often referred to as a "double cross" since the fingers are across two sets of seams.

Take the two seam grip & rotate the ball back toward the palm until the fingertips are in the middle of the bare leather. This pitch will be slightly slower than a two seam & tend to tail down at the plate. It is sometimes called a "no seam" fastball because the fingers aren't touching any seams.

Movement is a great thing. And throwing fastballs with different movement is very helpful in making pitchers effective.

Now, regarding pitch strategy.

Deception - The pitcher at times should use deception. E.g., follow an inside two seam with an inside no seam. It appears to be the same pitch coming in. But it will drop more as it approaches the plate. The batter is more likely to swing over the top. Or an outside double cross fastball followed by an outside changeup. Again, the pitch appears to be the same, but the different speed will throw off the batter.

Variation - The pitcher can vary from pitch to pitch. E.g., work the batter inside, then outside.

Pitchers can keep batters off balance by changing speed, location, movement (e.g., grip), angles. They can use deception or variation.

This is one part of pitch strategy. Another part is reading the batter.

Is the batter too close to the plate? Bust him inside with a fastaball. Then perhaps follow with something outside.

Too far off the plate? Work the outside corner until he moves up on the plate. Then bust him inside with a fastball.

Batter looks nervous, perhaps timid? Inside heat to remind him he is timid (as a great pitcher once said). Then perhaps work him away.

Does the batter hit with a closed stance? Again, work him inside, perhaps with a fastball angled in on his hands.

Does the batter use an open stance? Work him away, he won't be able to do anything with it.

An uppercut swinger? Pitch him up & in.

Has he chased a high pitch? Give him another on the inside, about 2-3" above the top of the zone. He will chase it all day long, but he won't be able to do anything with it.

A really hard swinger? How about a first pitch changeup to throw him off balance.

Behind on his swing? Stay with the heat, but change grips and location.

Ahead on his swing? Changeup time. Then mix it up.

Read the batter. Determine his tendencies, weaknesses & strengths.

The pitcher must never become predictable. On any count. Your pitchers need to be confident throwing a changeup on the first pitch or on a full count.

0-2? For sure nothing sweet, but maybe not a waste pitch either. For some batters, the changeup makes sense. For others, the inside fastball about 2-3" above the top of the zone will be impossible to lay off. Could be a fastball on the outside corner.

Keep batters off balance.

Whew, this is almost as long as an SK post. I'm sure I have left some things, and perhaps not be adequately clear. Let me know if I can confuse you more.

11YO's can have much more pitching savvy than most of us adults give them credit for.