Google did mention several times that for several APIs either the cost of maintenance goes high and not used much (or as much as expected) and it made Google to analyze the APIs at various point of time and depricate them. Way back in March 2011, Google have announced deprecation of its free version of translate API v1 (http://code.google.com/apis/language/translate/v1/getting_started.html). Now Google is launching the paid version of its translate API for business and commercial software products.
This API support translations between more than 50 languages and it is made possible by Google’s cloud infrastructure and large scale machine learning algorithms. If you look at the price range the translation cost $20 per million characters translated. The API console let you sign up of usage of up to 50 million characters per month.
Google will retain the limit of 100K characters per day for the users of Translate API Version V2 as curtsey till December 1. 2011.
News Source : Google