Another significant disadvantage of learning a foreign language at an early age
is that children will temporarily mix languages. Rehman states that “It is normal
for bi-/multilingual children to mix up languages until about the age of 4. If
children are lacking the right word in language A, they will borrow it from
language B to communicate their message”. It means that they may temporally
mix the languages affecting the way they interact or communicate their ideas or
messages to others.