The smartphone app now can read 27 languages and instantly convert the text without an Internet connection, the tech giant said.

Google also said it was making voice translation "faster and smoother" in the Translate app, which can interpret street signs, ingredient lists, instruction manuals and other texts.

The real-time text translation began with seven languages - English, French, German, Italian, Portuguese, Russian and Spanish.

The new ones added are Bulgarian, Catalan, Croatian, Czech, Danish, Dutch, Filipino, Finnish, Hungarian, Indonesian, Lithuanian, Norwegian, Polish, Romanian, Slovak, Swedish, Turkish and Ukrainian.

Additionally, one-way translations are available from English to Hindi and Thai.

Google's picture mode translation, which requires a snapshot of text, can operate in 37 languages.

The California group said the new features come from extensive research to develop so-called "convolutional neural networks," or using artificial intelligence to recognize letters and words and filter out backgrounds.

"We've still got lots of work to do," said product leader Barak Turovsky.

"More than half of the content on the Internet is in English, but only around 20 percent of the world's population speaks English. Today's updates knock down a few more language barriers, helping you communicate better and get the information you need," he said.