# The Polish vocabulary size test: A novel adaptive test for receptive vocabulary assessment

## TL;DR

The Polish Vocabulary Size Test (PVST) is a new adaptive tool that quickly and accurately measures how many words native and non-native Polish speakers know.

## Contribution

PVST introduces an adaptive testing method for Polish vocabulary assessment based on item response theory.

## Key findings

- Native Polish speakers had a mean vocabulary size of 75,125 words, much higher than non-native speakers (mean = 7,165 words).
- Vocabulary size in native speakers strongly correlated with age (r = .496, p < .001).
- PVST was validated with 1,475 participants and is available online at myvocab.info/pl.

## Abstract

We present the Polish Vocabulary Size Test (PVST), a novel tool for assessing the receptive vocabulary size of both native and non-native Polish speakers. Based on item response theory and computerized adaptive testing, PVST dynamically adjusts to each test-taker’s proficiency level, ensuring high accuracy while keeping the test duration short. To validate the test, a pilot study was conducted with 1475 participants. Native Polish speakers demonstrated significantly larger vocabularies (mean = 75,125 words; range = 19,556–122,693) compared to non-native speakers (mean = 7165 words; range = 646–23,394). For native speakers, vocabulary size showed a strong positive correlation with age (r = .496, p < .001). The PVST is available online at myvocab.info/pl.