These days there are many great apps for learning or looking up Japanese. Which ones are best for you will depend on what you want to do. Do you want to have fun learning? Are you a serious student? Do you want to look up words? Do you want to look up kanji? Or do you want a digital pen pal that will help you with your language?
Of course, it also depends on your operating system. The following are some of my favorites (with links included):
Learn Japanese by Mindsnacks for iOS is an application that helps you build your vocabulary. It uses games to introduce over 800 words and phrases in kana, kanji, and romaji. Quizzes help you practice and review.
Anki for Android (iOS version is not free) has flashcards from decks already installed, or ones you have created. Funny photos and cues make it entertaining as well as a great learning device.
FluentU for iOS and Android is a bridge between fun and serious as it uses video clips freely to make it engaging. It tracks your vocabulary focus and suggests videos and examples based on these. An upgrade for pay is also available.
Obenkyo for Android is a very easy-to-understand application that takes you through learning kana to kanji. Quizzes help you remember, and its handwriting recognizer will correct your stroke order and form.
Tae Kim's Guide to Learning Japanese for iOS and Android is a serious approach to learning. It provides structure for learning grammar, and clear explanations for words and phrases that have elusive meanings.
Japanese by Spacehamster for Android has a lovely design and makes lookups clear and easy. It has a handwriting recognizer and provides audio clips, kana and kanji for the look ups. The advertisements can get annoying, but you can get rid of them for a small fee.
Imiwa for iOS provides definitions in a variety of languages. It has an offline dictionary and will take you through the stroke order to help you learn a kanji character.
Waygo for iOS and Android is not a traditional dictionary. Instead, it allows you to take a picture of kanji you see and it will overlay the kanji with English, which is very handy in Japan (and China) if you're not up to par on your characters in Japanese, Mandarin or Cantonese. For more than 10 translations a day, you will need to upgrade to the paid version.
Digital Pen Pals:
ePenPal for Android provides a way to link up with someone in the same city, of the same age, and/or with the same hobby. It also features a group chat.
Lest Talk for iOS is like ePenPal. These apps let you find language partners so you can learn from others with a similar interest.
So what are your favorite language apps?