I got introduced to wordreference.com in French class at school, and it's honestly the best tool I've found for translations and writing in a foreign language. It's ideal for translating words and phrases between languages, as it gives additional information on how a word should be used, and what linking words need be added to it. It has dictionaries in Español, Français, Italiano, Português, Català, Deutsch, Svenska, Русский, Polski, Română, Čeština, Ελληνικά, Türkçe, 英汉词典, 英和辞書, 영-한 사전, قاموس إنجليزي - عربي, but there is only a limited number that can be translated between (see the drop down bar on the home page). It also has forums for if you can't find a particular phrase in the dictionary, where there are native speakers who can help you and where you can help others.