Gotera: Infants lack the motor ability required to voluntarily produce

EXPLANATION FROM Fox LSAT

Wait, what? Why would Gotera conclude that speech acquisition is “entirely motor control,” “rather than abstract or mental,” on the evidence she has provided? The evidence is: infants lack motor ability to voluntarily produce particular sounds, but can randomly babble. Most children are several years old before they can voluntarily produce most sounds. So what? Can’t they still be trying to ask for cookies? I say yes, Gotera seems to say no. Gotera has assumed that if you aren’t fully capable of producing the exact sound you want, then you can’t be using your brain at all when you attempt to produce a sound. This seems ridiculous.

A) I don’t really like this answer, but it could be the best of a bad lot. If A isn’t true, it becomes “speech acquisition is a function not only of one’s ability to produce the sounds of spoken language.” This would tend to undermine the conclusion that speech acquisition must be purely a motor control issue. I don’t love it, but if there’s nothing else decent we’ll have to choose A.

B) This seems way too specific. Did Gotera really assume this? I don’t think so.

C) No, the initial babbling stage might extend into early childhood without hurting Gotera’s logic at all. This can’t be it.

D) Can’t there be a prior stage? Gotera wouldn’t seem to care. So I doubt she assumed this.

E) Gotera doesn’t say that infants and children can’t control their tongues or mouths, and furthermore doesn’t say that they don’t have sophisticated mental development. This can’t be it.

The answer must be A, because it’s the only one we could really make a case for. Best of a bad lot.

Understanding the argument - 
­Gotera: Infants lack the motor ability required to voluntarily produce particular sounds, but produce various babbling sounds randomly. - Background Info. 

Most children are several years old before they can voluntarily produce most of the vowel and consonant sounds of their language. - Premise and continuation of background Info. 

We can conclude that speech acquisition is entirely a motor control process rather than a process that is abstract or mental. - Motor skill is a minimum condition for speech acquisition. 

Which one of the following is an assumption required by Gotera’s argument?


(A) Speech acquisition is a function only of one’s ability to produce the sounds of spoken language. - Means that "ability to produce sounds or motor skills is a minimum condition for speech acquisition. Ok. 

(B) During the entire initial babbling stage, infants cannot intentionally move their tongues while they are babbling. - "intentionally move their tongues" doesn't necessarily mean they can produce "the vowel and consonant sounds of their language" or "they have the motor skills." Moreover, this is precisely what the first premise said: "Infants lack the motor ability required to produce particular sounds voluntarily." Assumption is about stating the missing premise and not restating the premise. Wrong. 

(C) The initial babbling stage is completed during infancy. - Out of scope. 

(D) The initial babbling stage is the first stage of the speech acquisition process. - Out of scope. 
 
(E) Control of tongue and mouth movements requires a sophisticated level of mental development. - out of scope. 

Hello marty Murray

Can you please help me with answer choices A and B?

Please help me understand better.

Negating option B we get infants CAN INTENTIONALLY move their tongues. Meaning there is voluntary motor control and it kind of breaks the conclusion by saying that even if there is muscle control the infant is still babbling.