There is 1 myth in particular regarding small dogs, and that is the
barking issue. Some people falsely believe that small dogs are "yappers". This is generally not true. However, some breeds, such as the small Beagle do have a tendency to howl. Other small breed dogs such as the Pug often snort and snore....This is due to the shape of their heads, which allow for an extremely short snout and can cause breathing issues. The Maltipoo will not bark any more than any other breed.
With this being said, one must keep in mind that the environment that the dog is put into will influence many behaviors, including barking. For example, if put into a crate all day or left alone all day without a proper setup, the Maltipoo may bark from the moment the owner leaves the home until the second they return. Can you blame them? But, with proper care, training and some planning ahead of time, this breed will not have barking issues.