Intelligibility
Intelligibility refers to how successfully a speaker's message is received and understood by a listener. Smith and Nelson (1985) proposed a three-level distinction that has become the standard framework in ELF and World Englishes research.
Three Levels
| Level | Definition | What is recognised |
|---|---|---|
| Intelligibility | Word/utterance recognition | The listener can identify the words and sounds produced |
| Comprehensibility | Meaning | The listener understands the propositional content — what is being said |
| Interpretability | Intention/force | The listener grasps the speaker's communicative intention — why it is being said |
Example:
Speaker: "It's getting late, isn't it?"
- Intelligible if the listener recognises the words (getting, not getting misheard as getting)
- Comprehensible if the listener understands it refers to the time of day
- Interpretable if the listener recognises the implied suggestion to leave
Each level builds on the previous one, but they can break down independently. A speaker may be intelligible (words are clear) but not interpretable (the listener misses the pragmatic force).
Factors Affecting Intelligibility
| Factor | Impact |
|---|---|
| Segmental features | Consonant and vowel accuracy — the Lingua Franca Core identifies which are essential |
| Suprasegmental features | Nuclear stress placement is critical; rhythm and intonation are less so in ELF contexts |
| Shared L1 | Speakers with the same L1 find each other more intelligible, even with heavy accents |
| Familiarity | Exposure to a particular accent dramatically increases intelligibility |
| Context | Shared situational and topical knowledge supports comprehension |
| Speech rate | Excessively fast or slow speech reduces intelligibility |
| Lexical choice | Using idiomatic or culture-specific vocabulary can reduce comprehensibility across cultures |
Intelligibility vs Nativeness
A key insight from WE and ELF research: intelligibility and native-like accent are independent dimensions. A speaker can be highly intelligible without sounding like a native speaker, and a native speaker can be unintelligible to non-native listeners (through dialect, slang, or rapid connected speech).
Munro and Derwing (1995) demonstrated empirically that:
- Accented speech can be fully intelligible
- Listeners distinguish between accentedness (how different the accent sounds) and comprehensibility (how easy it is to understand)
- Heavy accent does not necessarily reduce comprehensibility
This has profound implications for pronunciation teaching goals.
Implications for ELT
- Goal setting — in most contexts, intelligibility (not native-like accent) should be the pronunciation teaching target
- Lingua Franca Core — Jenkins (2000) identified the phonological features essential for ELF intelligibility; these should be prioritised
- Receptive intelligibility — learners also need exposure to diverse accents to understand speakers from different L1 backgrounds
- Assessment — pronunciation assessment should evaluate intelligibility and comprehensibility, not proximity to RP or GA
- World Englishes awareness — teaching should validate diverse accents and challenge the idea that only Inner Circle varieties are "correct"
- Accent familiarity training — regular exposure to multiple accents improves listener comprehension more effectively than accent reduction training