Google Translate might not replace a human translator, missing nuance and occasionally providing some bizarre results, but if you only need a general idea of a sentence's meaning, the automatic translator works well. Both the Google Translate website and mobile app provide the same basic service, though each has a few unique tricks to offer.
The Web version of Google Translate can also translate entire websites. Set the languages, paste the website address, click Translate and then click the resulting link.
Tricks and Extras
Pick a source language in the app, tap the squiggly line icon and draw using your fingertip to insert a word or character: a big help for translating languages with characters you don't know how to type. The website offers the same feature. With the language set to Detect Language, click the pencil icon to open a space to draw using your mouse. Select the intended word or character to insert it for translation.
Tap or click the star icon on a translation to save it. In the mobile app, you'll find saved translations on the Starred tab. On the website, open the Phrasebook -- click the icon of a book with a star -- to see your saved items.
Translate a Photo or Speech (App Only)
Pick a source language in the app and then tap the camera icon or the microphone icon to translate from a photo or using your voice, respectively. To use the photo method, aim your camera at text, tap Scan and then highlight the text you want translated using your finger.
Translate a Document (Desktop Website Only)
Click Translate a Document, choose a file on your computer and click Translate to upload the file and translate it to the selected language. Google Translate supports text files and Word's DOC and DOCX files, but not OpenOffice's ODT files.