To get a quick translations of words, there are a few ways to do so.
Word Translation with Shortcut
Hold the Ctrl+Alt keys while highlighting a word. The Pop-up window opens with the word translations.
Word Translation without Shortcut
Highlight a word with the mouse. You will instantly see the word translations for a chosen language in the Pop-up window without pressing or holding any key.
To enable this mode, remove the Shortcuts from the Pop-up Bubble Options by clicking on X sign, and then Save Options.
To access Options right-click on the Google Translate button on the Opera toolbar and select Options.
Note: This translation mode is not recommended because it may interfere with other tasks where you make text selection with the mouse.
Word Translation on Double-click
You can also get a quick word translation by using the "Translate on double-click" feature.
Simply double-click on the word you want to see the translation, and the Pop-up window with available translations opens instantly.
To enable this feature go to the Pop-up Bubble Options and check mark the option "Translate on double-click".
Don't forget to Save options to record your changes.