That’s true, but also, speech-motor control develops throughout childhood, and one of the last things children develop is consonant clusters. This means words like (sp)a(gh)etti are harder for most children to say than, for example, “banana”, regardless of their language. Children tend to replace difficult clusters with one of their sounds, and when there’s more than one difficult cluster in a word, sometimes the other sound of one gets transposed in place of the other.