Duolingo English Test Spelling: What the Machine Marks

The Duolingo English Test is scored by software, and that fact tends to produce one of two reactions. Some candidates assume a machine will be forgiving about small slips, since it is only counting words. Others imagine a pitiless program docking marks for every stray letter. Neither picture is right, and the truth is more useful than either. Spelling counts in more of the test than most people realize, it counts in different ways in different tasks, and in one task your own familiar misspellings can be turned against you.

This guide goes through the test task by task, says what Duolingo's official guide and handbook say about how each is scored, and ends with a four-week preparation plan built on what memory research knows about learning spellings that last. The test is revised from time to time, so treat the official guide as the final word and check it in the week before you sit.

How the machine scores you

The test takes about an hour. After a short setup, you work through roughly 45 minutes of mixed, adaptive tasks, meaning that the questions become harder or easier depending on how you are doing, followed by a writing sample and a speaking sample. The result is an overall score from 10 to 160, in steps of five, along with subscores.

Scoring is done by what Duolingo calls a grading engine, trained to judge English in the way expert human raters do. Human proctors review every session, but their job is security, not marking. The team behind the test has described its design in the research literature, notably in a 2020 paper by Burr Settles, Geoffrey LaFlair and Masato Hagiwara on machine-learning-driven language assessment.

The tasks fall into two kinds. Some have a correct answer, and the engine compares yours with it. Others are open writing or speaking, and the engine judges their quality. Spelling matters in both kinds, but in very different ways, and it helps to know which is which. Other computer-scored exams work along similar lines, as our guide to PTE Academic spelling explains.

Where one wrong letter makes the answer wrong

In Read and Complete, you see a short passage in which some words have lost their second half, and you have three minutes to type the missing letters. The format is known to language testers as a C-test, and it has been studied since Christine Klein-Braley and Ulrich Raatz introduced it in the early 1980s. Each gap has one right answer, spelled exactly. Type "enviroment" and the answer is wrong; Duolingo's guide says a wrong answer here scores the same as a blank.

Fill in the Blanks works the same way, one sentence at a time, with around 20 seconds for each word. The handbook's examples include "disc" as the start of discovery and "ambi" as the start of ambiguous. Knowing roughly how a word sounds is not enough. You have to know how it is built.

This is where people who read well but spell by feel lose marks without noticing. You can understand a passage perfectly, know exactly which word belongs in the gap, and still type "definately." The engine does not give partial credit for good intentions.

Where spelling costs you less, but still costs you

Listen and Type plays a sentence, which you may hear up to three times, and gives you a minute to type it. This is dictation, one of the oldest exercises in language teaching, and the linguist John Oller argued in the 1970s that it tests listening, grammar and spelling all at once, which is why testers keep returning to it.

Duolingo says a missing word costs you more than a mistyped one. That is worth knowing, because it tells you what to do when you are unsure: type your best attempt rather than leaving a gap. But a mistyped word still costs something, and across many sentences the small losses add up.

Most of the lost marks here are not long, difficult words. They are the small words and endings that fast speech swallows. Unstressed function words such as of, to, the and have shrink to almost nothing when people talk. The final s on a plural or a third-person verb, and the ed on a past tense, are often barely audible. Then there are the sound-alikes: there, their and they're are identical on a recording, and so are to, too and two. The audio cannot tell you which one you heard. Only the grammar and meaning of the sentence can.

So the useful skill in Listen and Type is partly listening and partly reasoning. If the subject is she, the verb needs its s. If the sentence is about last week, the verb probably needs ed. If the word points to a place, it is there. Our list of homophones that confuse everyone covers the common traps.

The task that uses your own mistakes against you

Read and Select shows you a series of words, one at a time, and asks whether each is a real English word. You have about five seconds for each. It sounds like the easiest task on the test.

It is not, because of the fake words. Among the examples in Duolingo's own practice material are "atend," "outher," "grivious" and "sinfection." Look at them again. Each is a plausible misspelling of a real word. If you have been writing "atend" for attend for years, it will look entirely normal to you, and in five seconds your eye will say yes.

This is the clearest place where long-standing spelling habits carry a direct cost. A misspelling you have used a hundred times feels correct, precisely because you have used it a hundred times. The task measures, among other things, whether your mental picture of English words is accurate, and there is no way to fake that on the day. The handbook notes that both American and British spellings count as real words here, so colour and color are both safe.

How spelling counts in your writing

Several tasks ask you to write freely. Write About the Photo gives you a minute to describe an image, and the handbook suggests aiming for at least 30 to 40 words. Interactive Writing gives you five minutes on a question and then three more on a follow-up. The Writing Sample is a few minutes on one prompt, and the institutions that receive your score can read what you wrote.

The official guide lists the features the grading engine considers in writing, and spelling is named directly, under vocabulary, alongside word choice and word formation. So a spelling error is not a small separate deduction. It can count against your vocabulary, and when it produces a different real word, it can look like a grammar or word-choice error as well. Write "I want to loose weight" and the engine sees the wrong word, not a slip of the finger.

Remember, too, that the Writing Sample is read by people. An admissions officer who sees "recieve" and "goverment" in two sentences forms an impression that no score report can undo.

British or American spelling

Both are accepted in most of the test. The handbook says you may use American or British spelling in Write About the Photo, Listen and Type and Fill in the Blanks, and gives summarize and summarise as an example of two accepted forms.

There is one exception worth knowing in advance. The partial words in Read and Complete passages use American spelling. If you learned British English, expect center, color and traveling in those passages, and do not let them unsettle you.

In your own writing, choose one system and keep to it. A paragraph that switches between colour and color looks careless even though both are correct. The British versus American spelling guide sets out the main differences.

Practicing without a safety net

You type every answer inside the test, and you should prepare as if nothing will correct you. For many candidates this is the real shock. If you normally write with red underlines and silent autocorrections, you may have no idea how many words you depend on them for.

Find out now rather than on test day. For one week, switch off autocorrect and spell-check on your phone and laptop, and write as you normally would. The words that come out wrong are your real study list, and they will not be the words on anyone else's list. A structured way to find them is described in the twenty-minute self-audit.

Then build a ten-second check into every typed task. Do not reread your answer the way you read a story, because your eye will glide over errors and see what you meant. Look first at the endings of verbs and nouns, then at every small sound-alike word, then at any long word you were unsure of, read slowly syllable by syllable. The handbook suggests using the last seconds of the photo task to review, and the same habit pays everywhere.

A four-week plan

Four weeks of short daily sessions will do far more than one long weekend of cramming. That is not a motivational slogan. Nicholas Cepeda and colleagues showed in a large 2008 study that spreading study over days produces much better retention than packing it together, and that the ideal gap between reviews grows with the length of time you need to remember. For a test a month away, returning to each word every few days is about right.

In week one, find your words. Switch off autocorrect, do the self-audit, write three one-minute photo descriptions from any pictures you like, and try a few short dictations. Collect every word you get wrong or hesitate over.

In week two, do daily dictation. Find ten short sentences a day read by American speakers, from podcasts with transcripts, audiobooks with the text, or news clips with captions. Play each sentence, type it, then check it word by word. Every missed word goes on your list.

In week three, work on word parts and fake words. Learn the common endings such as tion, ment, ous and ible, and the common openings such as un, dis and re. Then try Read and Select in Duolingo's free practice test, and when a word looks almost right, ask what real word it resembles and how that word is actually spelled.

In week four, do one timed writing task a day and check every word afterward. Take the official practice test again at the end of the week, and compare it with your first attempt.

Throughout all four weeks, test yourself on your list instead of rereading it. Say the word, type it from memory, then check. Henry Roediger and Jeffrey Karpicke's 2006 experiments on what is called the testing effect showed that recalling information strengthens it far more than reviewing it, and spelling is no exception.

What to do next

Today, switch off autocorrect and write for ten minutes about anything at all. Underline every word you were unsure of. That is your starting list, and it is more accurate than any list of commonly misspelled words.

Then practice the way the test works: hear a word, type it, check it letter by letter. Spelling.School is built on exactly that loop, with a recorded voice, letter-level feedback and spaced review. Whatever you use, take Duolingo's free official practice test twice, once this week and once in your final week, so the format holds no surprises.

Questions people ask

Does spelling matter on the Duolingo English Test?

Yes, in several tasks. In Read and Complete and Fill in the Blanks you must type the exact letters of a word, so a misspelling makes the answer wrong. In Listen and Type a mistyped word costs you, though less than a missing word. In the writing tasks, Duolingo lists spelling among the features its grading engine considers under vocabulary.

Is the DET graded by a computer?

Yes. Duolingo says responses are scored by a grading engine trained to evaluate English the way expert human raters do. Tasks with a correct answer are compared with that answer, while writing and speaking tasks are judged on features such as vocabulary, grammar and coherence. Human proctors review every session, but their role is test security rather than scoring.

Which DET tasks test spelling?

Spelling matters most in Read and Complete, Fill in the Blanks and Listen and Type, where you type exact words. It also counts in Write About the Photo, Interactive Writing and the Writing Sample, where it is part of how vocabulary is scored. Read and Select tests spelling indirectly, because many of its fake words look like common misspellings of real ones.

Can I use British spelling on the Duolingo test?

Mostly, yes. The official handbook says American and British spellings are both accepted in tasks such as Listen and Type, Fill in the Blanks and Write About the Photo. The partial words in Read and Complete passages use American spelling. In your own writing, pick one system and use it consistently.

How do I practice spelling for the DET?

Start by turning off autocorrect for a week and listing the words you get wrong in your normal writing. Then practice short daily dictation, typing sentences you hear and checking them letter by letter. Test yourself on your list every few days instead of rereading it, and take Duolingo's free practice test at the start and end of your preparation.

Is there spell check on the Duolingo English Test?

You should not expect one. Answers are typed inside the test, so plan as if no spell-checker or autocorrect will help you. Practicing with autocorrect switched off before test day shows you which words you have been relying on it for, and those words make the best study list.

Fix the words you actually get wrong

A few minutes a day, spaced repetition, built only for spelling. Try five words without signing up.