Duolingo is a free website/app that allows access to languages. It is directly connected to a variety of languages including (but not limited to) Spanish, French, Mandarin Chinese, Irish, and Latin. Duolingo has little differentiation, but does provide differentiation from what may typically go on in a classroom. Duolingo requires motivation outside the app and should, in my opinion, not be assigned as required work for students. There are some concerns with regards to high frequency vocabulary, appropriateness of some content for students of varying ages, and the input it provides. With some languages it provides images and sound and for others there is writing and sound. 

Skitch is an app that can connect to any curriculum. It is an app that allows someone to take an image or document and mark it using notes, drawing, and emojis. Skitch provides a variety of differentiating options as it allows writing, arrows, emojis, exclamatory punctuation, etc. It is incredibly easy to use with little introduction. Skitch is available for free on Apple products but is made by Evernote, which is available across platforms. Examples below are from a Latin II class and include annotated versions of a story and a story listening activity.