15. The system of claim 9 , wherein the at least one processor is further programmed to compare the first timestamps and the second timestamps to check that words and sub-words appear in the right order according to their begin times.
9. A system comprising: at least one processor programmed to: receive a search query comprising a phrase comprising at least one in-vocabulary word and at least one out-of-vocabulary word; extract search terms from the phrase, the search terms comprising at least one in-vocabulary search term and at least one out-of-vocabulary search term; retrieve a first list of occurrences of words for the at least one in-vocabulary search term, the first list retrieved from a first index of words having first timestamps; retrieve a second list of occurrences of sub-words for the at least one out-of-vocabulary search term, the second list retrieved from a second index of sub-words having second timestamps; and merge the first list of occurrences of words and the second list of occurrences of sub-words to create a merged list, wherein merging the first list and the second list comprises evaluating the first timestamps and the second timestamps and adding to the merged list occurrences of combinations of words from the first list and sub-words from the second list that satisfy at least one evaluation criterion, wherein the at least one evaluation criterion comprises a threshold for a difference between first and second timestamps.