Phonological Mean Length of Utterance (PMLU)

The Phonological Mean Length of Utterance (PMLU) analysis scores each word for the number of phones and correctly produced consonants, reporting a mean value per participant.

The PMLU analysis calculates:
  1. Phonological Mean Length of Utterance (PMLU) (Ingram 2002)
  2. Expanded Phonological Mean Length of Utterance (ePMLU) (Arias & Lleó 2013)

The report output includes a summary of mean values for each participant and a detailed listing of the PMLU/ePMLU calculations for every aligned word pair.

Data Preparation

The analysis evaluates aligned IPA Target and IPA Actual words. Check syllabification and phone alignment before running the analysis. Assign a speaker to each record that should contribute to a participant's results.

Parameters

Use the PMLU parameter group to select the measures included in the report:

Option Effect
Ignore truncated words Exclude a target word when it has no aligned actual word. Enabled by default.
PMLU Include the PMLU and PWP columns. Enabled by default.
ePMLU Include the feature, syllable, ePMLU, and ePWP columns. Enabled by default.
Closed syllable bonus Add this value to the syllable score when the syllable begins and ends with a consonant. The default is 1.0.
Figure 1. Phonological Mean Length of Utterance (PMLU) Parameters
Phonological Mean Length of Utterance (PMLU) Parameters

Calculations

PMLU

PMLU_Target assigns one point to every target segment and one additional point to every target consonant. PMLU_Actual assigns one point when a target segment has an aligned actual segment. It adds another point when the aligned pair are consonants with the same base glyph; diacritics do not affect this comparison. Deletions and inserted actual segments receive no points. PWP is PMLU_Actual / PMLU_Target.

ePMLU Features

ePMLU_TargetFeatures assigns three points to every target consonant: one each for manner, place, and voicing. ePMLU_ActualFeatures assigns one point for each of those features that matches between an aligned target consonant and actual consonant. ePWP_Features is ePMLU_ActualFeatures / ePMLU_TargetFeatures; it is zero when the target score is zero.

ePMLUTarget Features = ttargetIPA { 0t is a vowel 3t is a consonant ePMLUActual Features = t,atargetIPA,actualIPA { 0t is a vowel (manner(t)=manner(a)) + (place(t)=place(a)) + (voicing(t)=voicing(a)) t is a consonant ePWPFeatures = ePMLUActual FeaturesePMLUTarget Features

ePMLU Syllables

ePMLU_TargetSyllables and ePMLU_ActualSyllables assign two points to every syllable in the corresponding transcript. A syllable whose phone pattern begins and ends with a consonant also receives the configured closed-syllable bonus. ePWP_Syllables is ePMLU_ActualSyllables / ePMLU_TargetSyllables; it is zero when the target score is zero.

ePMLUTarget Syllables = σtargetIPA { 2σ is open 2+closedSyllBonusσ is closed ePMLUActual Syllables = σactualIPA { 2σ is open 2+closedSyllBonusσ is closed ePWPSyllables = ePMLUActual SyllablesePMLUTarget Syllables

ePMLU

ePMLU_Target is ePMLU_TargetFeatures + ePMLU_TargetSyllables. ePMLU_Actual is ePMLU_ActualFeatures + ePMLU_ActualSyllables. ePWP is ePMLU_Actual / ePMLU_Target; it is zero when the target score is zero.

ePMLUTarget = ePMLUTarget Features + ePMLUTarget Syllables ePMLUActual = ePMLUActual Features + ePMLUActual Syllables ePWP = ePMLUActualePMLUTarget

Report Outline

A sample table of contents is displayed below. Bold level elements are section headers while italic items are tables.

  • Phonological Mean Length of Utterance (PMLU)

    • Parameters

    • Summary

      • All Participants

      • Participant 1

      • … for each selected participant
    • Listing (All results with PMLU/ePMLU calculations for each aligned pair)