comma before 'as well as' [conjunction]: learn the skills, as well as

[angel heart1]

Hi,

Could you please why there is a comma before as well as?

"Conversely, older ESOL learners must learn all the language skills simultaneously, as well as learn an adult vocabulary of multi-syllabic words."



Taken from: "Spelling it out! Accounting for Spelling Difficulties for Arab Learners of English By Helen Bowen"

Thanks.

 

[Chasint]

I think it is to avoid the reader parsing incorrectly by reading:

"...must learn all the language skills simultaneously as well" (in other words taking 'as well' to mean 'also')

Parsing that way would make the rest of the sentence unintelligible.

 

[angel heart1]

Thanks. Could please explain more?