Scientists have readied a list of 25 words which toddlers should be able to use.
The words and phrases that cover toys, food, animals and, of course, include 'mummy' and 'daddy' and 'bye bye', are designed to detect youngsters who may struggle with words in years to come, the Daily Mail reported.
The average child will know 150 of the words in the Language Development Survey but scores of 75 to 225 are normal. Alarm bells should start ringing if a toddler uses just 50 of the words or less, the American Association for the Advancement of Science's annual conference heard in Vancouver.
The 25-word list comprises mummy, daddy, baby, milk, juice, hello, ball, yes, no, dog, cat, nose, eye, banana, biscuit, car, hot, thank you, bath, shoe, hat, book, all gone, more and bye-bye.
Leslie Rescorla, who designed both versions of the test, said: "If children don't use most of these words by 24 months, they may be late talkers."
Many late-talkers are simply late bloomers, so Rescorla tells that if a child is otherwise developing normally, parents shouldn't panic. If the child, however, is still struggling for words by two-and-a-half, they should consider help.
Rescorla, of Bryn Mawr College in Pennsylvania, tracked the fortunes of 78 two-year-olds for 15 years. Half had been slow to start talking but didn't have any other problems.
By the time they reached 17, their vocabulary was classed as at least as good as average - but still wasn't as good as those who were better talkers as toddlers.
The late-talkers fared particularly poorly in tasks that involved 'verbal memory', or listening to words, sentences, or numbers and being able to repeat them.