Handing stress and intonation response

The API result will include the following lexical and intonation metrics:

1. syllable_score_list[]

   • stress_level: Expected lexical stress level based on the Lexicon. Possible values are,

     • 0: unstressed

     • 1: primary stress

     • 2: secondary stress

   • predicted_stress_level: Detected lexical stress level based on the user audio. Possible values are,

     • 0: unstressed

     • 1: primary stress

     • 2: secondary stress

   • stress_score: Floating point number between 0 and 100 indicating the correctness of the user's stress level.

   • pitch_range[]: [begin_pitch, end_pitch] - recorded for this syllable in Hertz.

2. word_intonation_list[]

   • syllable_intonation_list[]: [pitch_change_from_previous, pitch_change_in_current]

     • pitch_change_from_previous: indicates what is the pitch of a word from the previous syllable to the beginning of the current one

       • If we can’t recognize the syllable (due to error from our side or due to user not saying the syllable), the value is null.

       • If we can recognize the syllable but couldn’t determine the pitch (due to error from our side or due to user reducing the sound to unvoiced), the value is REDUCED.

     • pitch_change_in_current: indicates what is the pitch of a word from the beginning to the end of the current syllable

       • This value is null unless one of the following cases occurs.

         • If the pitch of the syllable falls, but the starting pitch of the syllable is higher than the ending pitch of previous syllable, secondary intonation is RISE while primary intonation is FALL.

         • If the pitch of the syllable rises, but the starting pitch of the syllable is lower than the ending pitch of the previous syllable, secondary intonation is FALL while primary intonation is RISE.

       • Possible values

         • RISE

         • FALL

         • FLAT

         • REDUCED

         • null

The lexical stress and the intonation results can be read as given in the example below:

word = "parent"

"syllable_score_list": [
{
  "phone_count": 2,
  "stress_level": 1,
  "letters": "pa",
  "quality_score": 100,
  "stress_score": 100,
  "intonation": [
    null,
    "FALL"
  ],
  "pitch_range": [
    226.71435643564357,
    211.65643564356435
  ],
  "predicted_stress_level": 1,
  "extent": [
    42,
    57
  ]
},

So if the array is intonation = [null, FALL] as seen above, then,

• from the previous syllable to the beginning of the current one, that is from some to pa = NULL

• from the beginning to the end of the current syllable, that is from start of pa to end of pa = FALL

You can use the intonation array and pitch range to compare the expected intonation against the actual intonation, visualizing this as an intonation staircase. This will enhance the test-taker's reading and speaking skills.