My understanding is that being dissociated is like or a kin to being hypnotized. you are in a very relaxed state of mind but you are also acutely aware of everything going on around you. Similar to how a person under hypnosis can "pick up" the given hypnotic suggestions that their cigarette has a foul taste, that enables a person to stop smoking.

picture a 5 yr old that has just undergone extreme trauma so they dissociated/self hypnotized their self. they are now an alter. that alter picks up every minute detail of what is going on around them that a normal person may not notice.

Example they happen to be sitting in a room with a person speaking english when their normal language is spanish. Their normal self will now speak spanish but the alter that picked up english now speaks the english words and phrases that they heard spoken.

picture a teen ager who that morning has undergone extreme trauma before school. part of their school routine is going to a german class. their normal language is english but they go to the class while dissociated. the alter ends up speaking german while the normal awake self speaks english.

Picture a 10 year old watching tv after undergoing extreme trauma. they are dissociated. that alter who is highly in tune to everything notices the sign language in the corner of the screen and pick that up.

picture an 8 yr old who is dissociated with nothing to do but sit there being as quiet as can be and notices the book that is printed in english, french, spanish and german.

Babies and children pick up things faster than adults do sometimes they dont have to see or ear every minute detail in order to learn things. A child or baby can learn the stove is hot just by reaching out and touching it. they dont understand it they just know by how it made them feel. language is the same way babies and children can pick up an amazing amount of a spoken, written or signed language with a very little amount of exposure.

now take your own abilities to learn something on your own. Alters are just like you. they are parts of a person that take on lives of their own, Some have the ability to learn and teach their self new things. if they want to learn a new language they can.

this is how I learned to speak many different languages. Some I learned in school language classes, some I picked up from the tv, some I picked up while in foster care during my short time of one week in one, some I picked up sitting in a court room lobby by watching people around me waiting to go in and testify against the person that hurt me. Some my alters taught their selves. Children have amazing learning capabilities even when dissociated.