At between twenty and twenty one months Felix has only a handful of words. Despite my lack of interest in so-called 'developmental milestones' I have become aware that this is not quite where he should be at his age. I hesitate to use the word delayed; children develop at their own pace and in their own unique order, just as a row of seeds planted at the same time will unfurl and grow differently.
His lack of language was highlighted when a friend visited with her toddler who is two months younger than Felix. Teddy had a word for everything; ball, cake, train, and upon spying our cat - confusingly also called Teddy - his eyes lit up with glee. The cat is now well versed in the ways of toddlers and after allowing himself to be clumsily fondled for a few minutes made good his escape. Teddy the toddler stood and pointed at his retreating form; 'Titty' he said. As a hybrid of Teddy and Kitty it takes some beating and his unintentional gag gave us a good laugh. I looked on in amazement as Teddy pointed at the items in The Hungry Caterpillar and named each one 'cupcake, sausage, apple, cherry pie'. Felix does not know a single word despite it being one of his favourite books. His entire vocabulary consists of 'daddy' and 'mama' 'baba' (for his Polish grandmother) 'nana' for his English, 'daffodil' 'bubble ‘bus’ and not a lot else. He makes a variety of appreciative noises to express pleasure and excitement, but no other concrete words have appeared for months. There is however an explanation for this apparent delay in his development, for Felix is trying to learn two languages. After Teddy's startling display I decided to undertake a little research and found myself delving into the roiling broth of myth and science surrounding language development in bilingual and multilingual children
Research
from the 1960' and 70's suggested that multilingual children acquire language
later and perform worse overall than monolingual children. There was thought to
be a detrimental effect on language and speech development, and these flawed
studies seemed to show that children raised with two languages struggle to
learn either properly. The research based conclusions on the fact that
multilingual children mix languages, sometimes in the middle of a sentence
(code switching) or pepper a sentence in one language with vocabulary from the
other (borrowing) Immigrant parents were encouraged to drop their natives
tongues and speak only in English, a disaster for their children as it
transpired that their children's language acquisition was harmed by being
taught in a language their parent were not confident in and thus struggled to
master the basic building blocks of speech. 
In recent years new research into speech and language development has made some startling findings. Consider this; within five days after birth all infants can tell the difference between two or more languages. It may take them six months to be able to separate them, especially if the two are similar, but they are immediately able to perceive the difference. A top international infant lab has produced a study showing that language acquisition begins in the womb, and that babies of mothers who spoke two languages during pregnancy responded to hearing both in the days post birth. Although opinion is now divided as to whether there is any delay in speaking for bilingual children, there is an understanding that this may sometimes happen as the child learns to distinguish and group words into each language. All this is mighty reassuring for those of us concerned that our haphazard approach to teaching two languages is confusing the hell out of our child and that perhaps we should just desist. This becomes ever more relevant as more and more people are raised with a dual heritage, born of couples who may not share a native language or of parents who are not both bilingual. This is the case in our household, where it is not as simple as speaking only Polish at home and English in public. My attempts to speak to Felix in Polish are sporadic as I tend to forget, but thank goodness his Polish 'babcia' speaks and sings to him primarily in Polish and has done since birth. All those Polish songs and rhymes he so loves hearing are finding their mark, and I am certain that in his own space and time he will order the confusion of words in his head and speak with confidence.
Just in case I needed an extra incentive,
there is solid evidence that bilingualism has a positive effect on cognitive
function outside of language. Bilinguals are better able to focus on tasks and
ignore distractions and irrelevant information, find understanding math’s
concepts and solving word problems easier, have enhanced reasoning and logic
skills and find learning other languages easier. Children raised in bilingual
households also have better self control, a key factor in school performance,
but the most fascinating and hopeful of all these benefits is that bilingualism
has been found to delay the onset of Alzeimers disease and dementia. The act of
switching between two different languages makes the brain active and flexible,
and just as older people are encouraged to exercise regularly to maintain bone
density and muscle strength so the aging brain needs its daily exercise to
remain supple. The knowledge that teaching Felix to speak my mother tongue may
benefit him from toddlerhood right through life, even to a liver spotted old
age that seems unimaginable in his unblemished baby skin, stopped me in my
tracks. So what if he has only a smattering of words? So what if he cannot name
the characters in his books or remember the word for cat? In his tiny and
endlessly agile baby brain an incredible double act is gearing up for
performance, one which can skip between tightrope and trapeze, tumble
effortlessly between any number of obstacles and fly with unerring precision
through all the hoops that life throws up. Ladies and Gentlemen, Boys and
Girls, please take your seats, the Incredible Bilingual Baby Brain Circus is
about to confound your expectations. 