Table 1.
Description of language and phone features analyzed in the study participants
| Definition/calculation | Measured skill | |
|---|---|---|
| Language features | ||
| Ratio of participant words | Total words produced by participant over total words produced in interview | Spontaneity in speech and willingness to speak, verbosity |
| Words per sentence | Mean number of words per sentence | Sentence complexity, verbosity |
| Words per second | Total words produced by participant over total duration of participant’s turns | Speed of speech production |
| Disfluencies per sentence | Mean number of disfluencies per sentence, including non-verbal and verbal edits, word repeats, and restarts | Ability to formulate sentences, fluency in conversation |
| Non-verbal edits per sentence | Mean number of non-verbal fillers (e.g., "uh", “ah”, "hmm”) per sentence | Speech fluency |
| Verbal edits per sentence | Mean number of verbal fillers (e.g., "like", "I mean", "you know") per sentence | Speech fluency |
| Word repeats per sentence | Mean number of word repeats and stutters per sentence (e.g., “I, I, I’m g-g-going out”). | Speech fluency |
| Restarts per sentence | Mean number of restarts (e.g., “did you call—phone him?”) per sentence | Speech fluency |
| Sequential word incoherence per sentence | Mean cosine similarity between sequential word embeddings per sentence | Semantic regularity |
| Pairwise word incoherence per sentence | Mean cosine similarity between embeddings of every word pair per sentence | Semantic regularity |
| Word uncommonness per sentence | Mean magnitude of word embeddings per sentence | Semantic regularity |
| Smartphone features | ||
| Phone usage missing days | Number of days in search window for which phone data are missing (i.e, available for less than 60 minutes per day). Search window=28 days before interview day, or number of days since previous interview (if <28 days) | Study compliance, ability to maintain routine |
| Phone use during sleep epoch (mean) | Mean minutes of phone in-use during sleep epoch over search window. See Methods for sleep epoch definition | Sleep quality |
| Phone use during sleep epoch (STD) | Standard deviation (STD) of mean phone in-use during sleep epoch over search window | Seep quality |
| Phone use during sleep epoch (days>0) | Number of days in data window for which phone in-use during sleep was greater than zero | Sleep quality |