At least half of the world's languages are expected to disappear before the end of the century, according to research by linguists in the US.

Researchers from Penn State University have found that by the end of the 21st century, 50 to 90 per cent of the world's languages will have fallen into disuse.

The researchers found 35 hotspots that are likely to witness language extinction. Of the 3,202 languages found - nearly half of all languages spoken on earth - at least 1,622 languages are likely to become extint within the next 90 years.

"We looked at regions important for biodiversity conservation [of human populations] and measured their linguistic diversity in an effort to understand an important part of the human dimension of these regions," said Larry Gorenflo, associate professor of landscape architecture at Penn.

With the loss of languages, some cultural information will also disappear.

"What ends up happening when we lose linguistic diversity is we lose a bunch of small groups [of people] with traditional economics," said Gorenflo.

"Indigenous languages tend to be replaced by those associated with a modern industrial economy accompanied by other changes. In terms of biodiversity conservation [of the human population], all bets are off," he added.

The researchers believe their study is a starting point to explore the relationship between biological and linguistic-cultural diversity. This will also help develop strategies for conserving species and languages in areas where rich diversity of both exists.

"We want to look at selected places with high biological and linguistic diversity to begin to explore the connections between the two, such as Tanzania, where there are 130-plus languages," said Gorenflo. "Also, the Indo-Burma hotspot in Southeast Asia, where there are nearly 400 languages, and the island of Vanuatu in the Pacific with 100-plus languages."