As a matter of fact, you can automatically translate your tweets (Twitter massages) from one language to another language with Google Translate, Tradukka, or some other online translation services, but you need to copy and paste the tweets before posting them on Twitter.
To make the translation and publish process more easier, you can use below 2 Twitter translation services, which will let you translate your tweets and post them on Twitter for free.
Twinslator supports 42 languages, you can change the translation before publish. Sign in with your Twitter accounts, then you can send both the original massages and the translated massages on Twitter, the translated massages will be published first, such as below:
Or you can just post the translated massages on Twitter.
Tweetrans support 45 languages, you sign in with Twitter OAuth, enter your massages and select the target language, then you can tweet the translated massages on Twitter, the tweets will look like below:
But you can’t change the translated massages before publish.
All the above two websites are powered by Google Translate, but easier to translate and publish massages on Twitter, since you can translate the messages and publish them on Twitter directly, no need to copy and paste.