While English is not an EL's native tongue they can still apply the usage of nouns, verbs and adjectives to English. Concepts that should have already been grasped in their native language.
All language rests on innate building blocks of expression
Threshold Hypothesis
Jim Cummins
A certain proficeiency in first language must be reached before learning a second language.
If a new EL student has not had the opportunity to grasp their native tongue to an extent their development of the English language as L2 will suffer.
Input Hypothesis
Stephen Krashen
We cannot acquire language just by talking, it must come from the understanding of the message.
A teacher can say "repeat after me" to an EL all day, but until they communicate the message i.e drawing for explanation, the words mean nothing.
Critical Period Hypothesis
Eric Lennberg
L2 is more difficult to become proficient in after lateralization is completed. Best to learn L2 between age 2 and puberty.
A child entering a kindergarten classroom is going to be able to better adapt to a new language than an adult attempting to learn a second language.
BICS (Basic Interpersonal Communicative Skills)
Jim Cummins
Our fluent conversational language learned by an early age.
Two kindergartens discussing their weekend with language they have been exposed to
CALP (Cognitive Academic Language Proficiency)
Jim Cummins
Not typical everyday langauge. Often takes 5+ years of catching up in verbal and written.
Words that are difficult for a native English speaker can take even longer for an EL student to grasp because they are not words used very often.