Vowels, monophthongs and diphthongs

Cambridge Veritas · Original TESOL self-study resources

Understand the idea

Vowel quality depends on the shape of the vocal tract. A monophthong has a relatively steady quality, whereas a diphthong involves a glide. Descriptions and symbol choices vary by accent, so specify the model and avoid treating all English speech as identical.

What you will practise

• Explain the key idea in “Vowels, monophthongs and diphthongs” using a concrete example.
• Choose a teaching response that fits the learner and the purpose.
• Identify evidence you could collect to evaluate that response.

A closer look at the teaching

Vowels are best explored through listening and noticing, with spelling introduced as a separate question. Compare a small set in the chosen accent and discuss tongue or lip movement only where it helps. A diphthong is a sound movement, not simply two adjacent vowel letters on the page.

Sound awareness supports a teacher’s decisions about pronunciation, vocabulary and listening. Distinguish spoken units from written letters and examine contrasts in a stated pronunciation model. Physical descriptions and phonemic symbols can be helpful, but their value depends on what learners can hear and communicate. Move between listening, a manageable articulation cue and word-level use, then test the contrast with a listener rather than assume that chart knowledge establishes a practical skill.

In the classroom

Before choosing an activity, identify what the learner needs to understand or communicate. Separate the language demand from other demands such as reading instructions, managing equipment or speaking to a large group.

A teaching sequence you can adapt

Use these stages as a starting point for this topic. Keep the language goal visible, and change the support when learner responses show a different need.

1. 01

   Choose a relevant contrast and check whether the learner can identify it in familiar words.

2. 02

   Model the sound and offer a simple cue about articulation or voicing where that helps.

3. 03

   Rehearse words and short phrases, connecting the sound with a useful written or phonemic record.

4. 04

   Use a listener identification task and revisit either perception or production according to the result.

A common mistake to avoid

When reviewing the activity, distinguish what you observed from what you inferred. Use the task outcome and a fresh example to decide whether another explanation, a different scaffold or more independent practice is needed.

Adapt it for your learners

Keep the intended outcome consistent when comparing responses. Record which support was available so you do not confuse a supported performance with the same task completed independently.

Try it, then compare.

Take a moment to make your own decision. Compare your reasoning with the example, then adapt it for a teaching context you know.

Your questions, answered.

Quick revision

• The key idea: Vowel quality depends on the shape of the vocal tract.
• The context to remember: In many accents, the vowel in “day” glides while the vowel in “bed” is relatively steady.
• A useful next step: Plan a noticing activity without relying on spelling.

For your teaching portfolio: keep a brief plan, a note of what learners actually did and one change you would make next time. Use anonymous examples.

Sources and authorship

This module maps to the supplied syllabus PDF, The sounds of English (6 pages). The study notes, examples, application tasks and self-checks on these pages are original Cambridge Veritas resources.

View the supplied PDF ↗ · Publication reference: source chapter

Written by Cambridge Veritas. Updated 10 November 2026.

Use these resources for preparation and reflection. Browser self-check results are for personal study and do not award a qualification or replace observed teaching practice.

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