Lingua is a free resource that offers reading, listening, dictation, and vocabulary activities.
Every day, the site provides six new dictations in your target language. You can listen to two separate native speakers reading a series of sentences first at a normal speed, and then a slower speed. After you have finished transcribing, the website will automatically check and correct your writing.
There are also short readings and listening comprehension exercises accompanied by a reading comprehension quiz on the side. The difficulty of content available depends on the language. Each exercise focuses on a theme relevant to everyday life, such as family, travel, and activities. Although each reading piece seems to have been written by native speakers, you may catch a few grammatical errors within the texts.
You can choose to quiz either your passive or active vocabulary with a flashcard-like activity, although you may want to make personalized flashcards on Anki or use pre-made decks on Brainscape for a more curated practice.
It’s probably possible to get through most of Lingua’s content in a month, as there are only a handful of exercises in each language. Nevertheless, it’s a solid supplementary resource for reading, listening, and dictation practice.