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Harvard Sentences: Complete List, Examples, PDF, and Generator

Published March 27, 2026 · Updated June 14, 2026 · 12 min read

Whether you're an audiologist testing hearing aids, a linguist studying phonetics, or an engineer evaluating text-to-speech systems, chances are you've encountered Harvard Sentences. These carefully crafted sentences have been the gold standard for speech intelligibility testing for over half a century.

In this guide, we'll cover everything you need to know about Harvard Sentences — their history, structure, examples, download formats, how they're used, and how you can work with them using our interactive tool.

If you need the actual sentences, use the Interactive Harvard Sentences Tool to browse all 720 Harvard Sentences, filter by list, generate random examples, download PDF or CSV lists, view IPA transcriptions, and play each sentence with text-to-speech.

What Are Harvard Sentences?

Harvard Sentences are a collection of 720 phonetically balanced sentences used to test the intelligibility of speech in various audio and communication systems. They were originally developed at Harvard University's Psycho-Acoustic Laboratory during World War II, when researchers needed a reliable way to evaluate the clarity of military communication equipment.

The sentences were later standardized by the IEEE as IEEE 297-1969, formally titled "Recommended Practice for Speech Quality Measurements." This standard has since become the definitive reference for speech intelligibility testing worldwide.

Each sentence is short, simple, and constructed so that key words can be scored for intelligibility. For example:

  • "The birch canoe slid on the smooth planks."
  • "Glue the sheet to the dark blue background."
  • "A pot of tea helps to pass the evening."
  • "A rich farm is rare in this sandy waste."

Harvard Sentences List

The complete Harvard Sentences list contains 720 sentences. They are grouped into 72 lists, with 10 sentences per list. This format makes them practical for controlled voice recording and speech intelligibility testing because each list can be used as a compact test set.

How Many Harvard Sentences Are There?

There are 720 Harvard Sentences in the standard corpus. The sentences are divided into 72 numbered lists, and each list contains 10 sentences. A single list is usually enough for a short speech intelligibility trial, while multiple lists are useful when you need broader phonetic coverage or repeated measurements.

This structure is also why Harvard Sentences are convenient for recording sessions: you can assign one list at a time, keep filenames organized by list and sentence number, and avoid repeating the same prompts during multiple test rounds.

Harvard Sentences Examples

Here are common Harvard Sentences examples from the corpus:

  • "The birch canoe slid on the smooth planks."
  • "Glue the sheet to the dark blue background."
  • "The boy was there when the sun rose."
  • "A rod is used to catch pink salmon."
  • "A pot of tea helps to pass the evening."

You can use examples like these for microphone checks, pronunciation practice, short voice samples, and quick TTS or ASR trials. For controlled testing, use a complete numbered list instead of picking only familiar examples.

For most use cases, you do not need to use all 720 sentences at once. A typical workflow is:

  1. Choose one or more lists.
  2. Record or play all 10 sentences in each list.
  3. Score listener responses or compare system output against the reference text.
  4. Move to another list if you need more coverage or repeated trials.

You can browse the full collection in the Harvard Sentences list tool. The tool includes:

  • All 720 Harvard Sentences.
  • List filtering from List 1 to List 72.
  • Random sentence and random list generation.
  • PDF download for the complete corpus or selected list.
  • CSV export for spreadsheets, scripts, and experiments.
  • Copy selected list for test protocols or recording scripts.
  • IPA transcription for each sentence.
  • Text-to-speech playback.
  • Adjustable speech rate, pitch, and voice selection.

This is useful if you are preparing a voice recording session, testing microphones, evaluating a TTS system, or looking for phonetically balanced sentences without copying a static list manually.

Harvard Sentences PDF and CSV Downloads

Many people search for a Harvard Sentences PDF because a printable list is useful during recording sessions, speech tests, and classroom exercises. The Harvard Sentences tool lets you download either the complete 720-sentence corpus or the currently selected list as a PDF.

If you need a machine-readable format, use the CSV export. CSV is better for spreadsheets, ASR evaluation scripts, TTS test harnesses, and experiment logs because it preserves the list number, sentence ID, sentence text, and IPA transcription in separate columns.

Can I Download Harvard Sentences Audio or WAV Files?

The interactive tool provides text-to-speech playback in the browser, but it does not currently ship pre-recorded WAV files. That distinction matters: browser TTS is useful for quick listening, pronunciation reference, and rough playback, while WAV files should come from a controlled recording process if you need research-quality audio.

If your goal is to create Harvard Sentences audio files, the practical workflow is:

  1. Download the PDF or CSV list.
  2. Record each sentence with consistent microphone placement, room conditions, and speaking style.
  3. Save files by list and sentence number.
  4. Review each recording for clipping, noise, and missed words.

This gives you cleaner audio than relying on generic generated speech files.

Structure of the Harvard Sentences

The 720 sentences are organized into 72 lists, each containing 10 sentences. This structure is intentional:

Phonetic Balance

Each list is phonetically balanced, meaning it contains a representative distribution of English phonemes (distinct speech sounds). This ensures that testing with any single list provides a fair assessment of speech intelligibility across the full range of English sounds.

In practical terms, phonetically balanced sentences are sentences selected so that the sounds of a language appear in roughly representative proportions. This matters because a speech test should not overrepresent only easy sounds or avoid difficult sounds. A balanced list gives a more reliable signal about speech clarity, pronunciation, audio quality, or system performance.

Keyword Scoring

Each sentence contains five key words that can be scored for intelligibility. When a listener repeats back what they hear, the tester counts how many of the five key words were correctly identified. This gives a percentage score — for example, getting 4 out of 5 keywords correct in a sentence yields 80% intelligibility for that sentence.

Simple Vocabulary

The sentences use everyday vocabulary and simple grammatical structures. This is by design — the test should measure how well the audio system transmits speech, not how well the listener knows obscure words.

Why Harvard Sentences Matter

Harvard Sentences remain the standard for speech testing because of their reliability, consistency, and wide acceptance across disciplines. Here are the primary use cases:

1. Audiology and Hearing Aid Fitting

Audiologists use Harvard Sentences to evaluate a patient's ability to understand speech. By playing sentences through calibrated speakers or hearing aids, they can measure:

  • Speech recognition thresholds — the quietest level at which speech is understood
  • Word discrimination ability — how well a patient distinguishes between similar-sounding words
  • Hearing aid effectiveness — whether a hearing aid improves speech intelligibility in various conditions

2. Telecommunications and VoIP Quality

Telecom engineers use these sentences to evaluate call quality across networks. Since the sentences are phonetically balanced, they provide a standardized way to test:

  • Audio codec quality
  • Network latency effects on speech clarity
  • Noise cancellation performance
  • Speaker and microphone quality

3. Text-to-Speech (TTS) Evaluation

Developers building TTS systems use Harvard Sentences to evaluate how natural and intelligible their synthesized speech sounds. The phonetic balance ensures all English sounds are tested, revealing weaknesses in specific phoneme synthesis.

4. Speech Recognition Benchmarking

Automatic speech recognition (ASR) systems are benchmarked against Harvard Sentences to measure accuracy. Since the sentences are well-known and standardized, they provide a consistent baseline for comparing different ASR engines.

5. Acoustic Research

Researchers studying room acoustics, noise reduction, and audio processing algorithms rely on Harvard Sentences for reproducible experiments. The standardized corpus ensures that results can be compared across studies.

Harvard Sentences for Voice Recording

Harvard Sentences are useful for voice recording because they are short, standardized, and phonetically balanced. This makes them a practical script when you need speech samples that cover a broad range of English sounds.

Common voice recording uses include:

  • Microphone and audio interface testing.
  • Room acoustic checks.
  • Speech dataset collection.
  • TTS voice evaluation.
  • ASR or transcription testing.
  • Pronunciation and accent analysis.

For a clean recording session:

  1. Pick a fixed number of lists before recording.
  2. Use a quiet room and consistent microphone placement.
  3. Record at the same volume and speaking style across all sentences.
  4. Leave a short pause between sentences.
  5. Keep file names organized by list and sentence number.
  6. Review recordings for clipping, background noise, and missed words.

If you only need a short voice sample, start with one or two lists. If you are building a larger speech dataset, rotate through more lists so your recordings cover more phonetic variety.

Harvard Sentences for Voice Cloning and TTS Evaluation

People also search for Harvard Sentences for voice cloning because the sentences provide a compact way to record varied English sounds. They can help create structured voice samples for research, TTS evaluation, or personal voice experiments.

Use them carefully. For any voice cloning workflow, only record:

  • Your own voice.
  • A speaker who has clearly agreed to the recording and intended use.
  • Audio that follows the rules of the tool or platform you are using.

Harvard Sentences can help with coverage, but they are not a complete voice dataset by themselves. A high-quality TTS or voice model may also need different speaking styles, longer passages, emotional variation, noise-free audio, and consistent recording conditions.

For evaluation, Harvard Sentences are often more useful than random text because they make it easier to compare pronunciation, intelligibility, and phoneme coverage across systems.

IPA Transcriptions

For linguists and language learners, International Phonetic Alphabet (IPA) transcriptions are invaluable. IPA provides a precise notation for the pronunciation of each sentence, removing ambiguity that exists in standard English spelling.

For example:

  • Text: "The birch canoe slid on the smooth planks."
  • IPA: /ðə bɜrtʃ kəˈnu slɪd ɑn ðə smuð plæŋks/

IPA transcriptions are useful for:

  • Speech therapy — helping patients produce specific sounds correctly
  • Language learning — understanding exact pronunciation of English sounds
  • Phonetic research — analyzing the phonemic content of each sentence
  • TTS development — verifying that synthesized speech matches expected pronunciations

How to Use Harvard Sentences

For Speech Intelligibility Testing

  1. Select a list — Choose one of the 72 lists. Each list is independently phonetically balanced.
  2. Present the sentences — Play each sentence through the audio system being tested.
  3. Score the responses — Count how many key words the listener correctly identifies out of 5 per sentence.
  4. Calculate intelligibility — Average the scores across all 10 sentences for an overall percentage.

For TTS and ASR Evaluation

  1. Feed sentences to the system — Use multiple lists to cover all phonemes.
  2. Record output — For TTS, record the synthesized audio. For ASR, collect the transcriptions.
  3. Compare against reference — Score accuracy against the known correct text.
  4. Analyze weaknesses — Identify specific phonemes or sentence structures that cause errors.

Try the Interactive Harvard Sentences Tool

To make working with Harvard Sentences easier, we built an Interactive Harvard Sentences Tool that includes:

All 720 Sentences with IPA

Browse the complete collection of Harvard Sentences organized by list, each with its full IPA transcription. Filter by list number to focus on specific sets.

Text-to-Speech Playback

Listen to any sentence using your browser's built-in text-to-speech engine. You can:

  • Play individual sentences — Click the play button next to any sentence
  • Play an entire list — Use the "Play All" button to hear all sentences in sequence
  • Adjust speech rate — Slow down (0.5x) or speed up (2x) the playback
  • Adjust pitch — Modify the pitch to simulate different speaker characteristics
  • Choose voices — Select from available TTS voices on your device

PDF, CSV, Copy, and Random Generator

Export the complete Harvard Sentences list or the currently selected numbered list as a PDF for printing. Use CSV when you need structured data for spreadsheets, scripts, ASR checks, or TTS evaluation workflows. You can also copy the selected list directly or use the random sentence/list generator for quick practice prompts.

List Filtering

Quickly jump to any of the 72 lists using the searchable dropdown. Each list shows the sentence count, making it easy to navigate the full collection.

Auto-Scroll

When playing through a list, the tool automatically scrolls to keep the currently playing sentence in view — no manual scrolling needed.

Try the Interactive Harvard Sentences Tool →

Conclusion

Harvard Sentences have stood the test of time as the standard corpus for speech intelligibility testing. Their phonetically balanced structure, simple vocabulary, and keyword scoring system make them indispensable across audiology, telecommunications, speech technology, and linguistic research.

Whether you're evaluating a new hearing aid, benchmarking an ASR system, or studying English phonetics, Harvard Sentences provide a reliable and standardized foundation for your work.