Alterations: From Size 5T to Itty Bitty

 tiny size for our nearly one year old Alexander

tiny size for our nearly two year old Brooklyn

"teenager size" for our three year old, John Jeffrey; his shirt is the original size as purchased

Stores offer youth small or toddler sizes of shirts.  I found cute ones in size 5T which is explained as "teenager" size by John Jeffrey as he proudly sort of fits into that size!  The younger grandchildren are wearing modified size 5T; first cut off the sleeves and take them in at the shoulders for at least 2 inches.  Then seam up the sides about 2 inches on each side.  They fit rather well considering I did not modify the necks and since both little cuties are not here to measure!