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PGU Calculator

Percent Grammatical Utterances from a pasted language sample. Tap G or U per utterance and the calculator returns PGU live, plus the Eisenberg & Guo (2013) severity band once you have scored 25+ utterances. Data stays in your browser.

PGU %Eisenberg & Guo 2013Mobile ScoringClient-Side
Tool details, related tools, and citation

Paste your language sample

One utterance per line. Mark each utterance as grammatical or ungrammatical below; the calculator returns Percent Grammatical Utterances across the scored subset.

Paste a transcript above, then score each utterance as grammatical or not to compute Percent Grammatical Utterances.

Get the full analysis

Unlock normative comparison and error analysis

This free tool covers the basic case. ConductSpeech adds normative comparison, error categorisation, and a parent-ready report.

Get the full analysis with ConductSpeech
  • Computing PGU from a transcribed language sample for an evaluation or progress report
  • Tracking grammaticality growth across sessions for a child with Developmental Language Disorder
  • Reporting a grammaticality index alongside MLU and NDW for a complete LSA description
  • Teaching graduate SLP students how PGU complements MLU and lexical diversity
  • Screening a caseload child for whom MLU alone looks normal but grammatical errors are frequent

Don't use for

  • Scoring samples below 25 utterances — the severity bands are unstable
  • Diagnosing DLD from PGU alone — combine with MLU, lexical diversity, and narrative measures
  • Judging AAE or other dialectal productions against mainstream American English grammar rules
  • Auto-flagging ungrammatical utterances — that requires clinical context (use ConductSpeech for error categorisation)
  • Reporting PGU across bilingual samples without a parallel score for each language

What Is Percent Grammatical Utterances?

Percent Grammatical Utterances (PGU) is the percentage of a child's utterances that contain no grammatical errors. It is one of the three core descriptive dimensions of a language sample alongside length (MLU) and lexical diversity (TTR / NDW). PGU captures grammaticality — whether the child marks tense, agreement, plurals, articles, and pronouns correctly — which is a different axis from either sentence length or vocabulary variety.

Why it matters. PGU is the single most sensitive language-sample index of Developmental Language Disorder (DLD). Children with DLD consistently score 10-15 percentage points lower on PGU than typically developing peers, even when their MLU is age-appropriate. A child who produces long utterances that are riddled with morpheme omissions will look fine on MLU and low on PGU — a pattern that only emerges when you report both measures.
How it is computed. Score each utterance as grammatical (G) or ungrammatical (U). The numerator is the count of G utterances; the denominator is the total number of utterances you scored. Utterances you leave unscored (unintelligible, imitations, maze behaviour) do not enter either the numerator or the denominator.

Interpreting PGU — Eisenberg & Guo (2013) Bands

Eisenberg & Guo (2013) established the most widely cited reference for PGU severity bands, based on a sample of preschool and school-age children with and without language disorder:

  • >= 93% grammatical — Typical range. Matches the mean PGU of typically developing preschool and school-age children.
  • 78% - 92% grammatical — Borderline / clinical concern. Warrants closer evaluation with additional measures (MLU, lexical diversity, narrative).
  • < 78% grammatical — Clinical concern. Consistent with Developmental Language Disorder. Does not substitute for a full diagnostic workup.

The calculator assigns a severity band only once you have scored at least 25 utterances. Below that threshold, PGU is unstable and can swing by 10+ percentage points with a single reclassification. Always score 50+ utterances before including PGU in an evaluation report.

How This Calculator Works

Paste your language sample into the textarea, one utterance per line. The calculator:

  • Splits the sample into utterances using the shared SLP utterance parser (newlines first, sentence-ending punctuation as a fallback).
  • Renders a scoring table with a Grammatical / Ungrammatical toggle per utterance and a 44px touch target for mobile use.
  • Reports PGU percentage, scored count, ungrammaticality count, total utterances, and total words as you score.
  • Assigns an Eisenberg & Guo (2013) severity band once you have scored at least 25 utterances.
  • Stores your scores in component state — nothing is uploaded, nothing is persisted across a refresh.

Tap the G / U buttons to toggle a score; tap the same button again to un-score an utterance. Unscored utterances stay out of the PGU denominator.

Frequently Asked Questions

Next Steps

MLU Calculator — pair PGU with MLU-morphemes from the same sample

Read guide →

Lexical Diversity Calculator — TTR, NDW-100, NDW-50

Read guide →

Brown's Stages Lookup — grammatical milestones by stage

Read guide →

SUGAR Norms Lookup — age-matched reference values

Read guide →

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