1. A method comprising: receiving a search term; identifying instances of the search term in a source text; for each of the instances of the search term identified in the source text, identifying a prefix string comprising a plurality of tokens preceding the search term in the source text, and identifying a suffix string comprising a plurality of tokens subsequent to the search term in the source text; providing data to display a visualization interface that comprises the search term within a combined tree diagram comprising a prefix tree extending to a first side of the search term, and a suffix tree extending to a second side of the search term, such that the prefix tree displays, in a tree diagram format, the prefix strings for the instances of the search term identified in the source text, and the suffix tree displays, in a tree diagram format, the suffix strings for the instances of the search term identified in the source text, wherein the prefix tree comprises tokens that are shared in common among the prefix strings as nodes connected to adjacent tokens by branches, and the suffix tree comprises tokens that are shared in common among the suffix strings as nodes connected to adjacent tokens by branches, wherein the branches in the prefix tree and the suffix tree are user-selectable in the visualization interface; and providing, in response to receiving a user input selecting one of the branches in the prefix tree or in the suffix tree, data to display a visual indication of a prefix string and a suffix string in the visualization interface that form a matching sequence of prefix string, search term, and suffix string that originate together in the source text, for each of one or more matching sequences that are connected through the selected branch.