1. A computer-implemented method comprising: determining, by a server, a level score of a learner based upon a plurality of responsive inputs received from a client device associated with the learner during one or more sessions associating at least one server with a browser of the client device, wherein, during a session of the one or more sessions, the server is configured to receive from the client device one or more responsive inputs of the plurality of responsive inputs via one or more networks; determining, by the server, a pedagogical value threshold based upon the level score of the learner and a resource difficulty score of a resource containing text having one or more words; storing, by the server, into a keyword store, each word of the one or more words having a word difficulty score satisfying the pedagogical value threshold, wherein the keyword store is hosted on one or more computers comprising non-transitory machine-readable storage media configured to store each of the words of one or more resources; selecting, by the server and from a resource store, the resource comprising content associated with one or more learner attributes of the learner using the words satisfying the pedagogical value threshold; identifying, by the server, a type of learning activity that exercises a language skill for improvement of the learner and corresponds to a goal of the learner; identifying, by the server, one or more records in a distractor store containing a set of one or more distractors of a type suited to the identified type of learning activity; and generating, by the server, a learning activity of the identified type of learning activity utilizing at least one of the set of one or more distractors extracted from the selected resource.