Humans can learn new words and different accents but the same can't be done by all living beings. A debate is going on in the science community, and it has driven scientific progress. Scientists are debating on whether chimpanzees can really learn new words and accents or not.

Although the subject is not that exciting as the major scientific debates of history, still if it can be proved that chimpanzees have accents and can learn new words, it may help in revealing significant information about primate intelligence.

The well known gorilla Koko has already learned more than a 1,000 signs of sign language. It was able to communicate complex ideas and thoughts to human beings. This was something that disproved the idea that primates can't learn language. Still, the complexity of smaller primates, including chimps, is unknown.

Researchers started exploring the notion when they noticed that chimps, who were moved from a Netherlands safari park in 2010, to an Edinburgh zoo, had subtly different calls from the 'Scottish' chimps, who were already present there.

The researchers interestingly discovered that the calls of the newly arrived chimps slowly changed with the passage of time. Particularly, the way they call for apples, seemed to change when they arrived.

The calls of Netherlands chimps, at first, were rather excited and high pitched, but gradually the calls become low and lethargic, alike the Scottish chimps.

Warwick University's Dr Simon Townsend, who co-wrote the original paper with colleagues in York and St Andrews, told the BBC: "We think that we've addressed the points that they bring up. It's an interesting critique of our research - and this is exactly how science works."

After three years in their new home, the Dutch group had shifted from calling for apples with a high-pitched, excited grunt, to a low-pitched one that more closely matched the rather unenthusiastic "apples" call used by the Edinburgh chimps.

This was noteworthy because the Dutch animals, before and after the move, really liked apples - and such calls were generally thought to be closely fixed to the emotional value of the food concerned.

Dr Townsend and colleagues, meanwhile, have also re-plotted the data, tracking changes in individual chimps over time - emphasising the original difference, and convergence towards lower-pitched calls across the three years.

One of the critics, Dr. Brandon Wheeler, an anthropologist from the University of Kent in the UK, suggests that a closer look at the data shows that both the Dutch and the Scottish chimps “largely overlapped in the range of calls they were originally giving in response to the apples,” he said the BBC News report.

The researchers failed to rule out simple explanations such as the Dutch animals being more excited about apples than the Scottish animals or feeling insecure in their new surroundings, Fischer added.

Julia Fischer of the German Primate Center, New York University's James Higham and the University of Kent's Brandon Wheeler, re-analyzing the study for the same journal, questioned its methods and said the researchers misrepresented data and failed to rule out alternative explanations.

Finally, the critics argue that the higher-pitched calls could simply reflect greater excitement in the Dutch chimps, following their move, which settled down over time.
But Dr Townsend and his colleagues suggest that, if this were the case, you might expect a parallel change in the Edinburgh chimps' behaviour, as they adjust to their new companions - which does not seem to be the case.

The scientists, supporting this change, speculated that either the chimps have learned a new word, or they have altered their accent, both of which would be noteworthy changes.