One word per charge: why a lesson would fail

A phone gets plugged in several times a day, and each plug-in is a moment that lasts a few seconds. Vocabcord plays one word in that moment: the word, a pause, its translation, a pause, the word again. One word survives where a lesson would die, and a weighted decay sampler picks which one, favouring the words you are about to forget.

What plays when you plug in

The whole event is short. Plug in the charger and the app speaks the target word, waits, speaks the translation, waits, then speaks the target word once more. The first pass is the meeting, the pause after the translation is where you try to say it back, and the second pass checks you. That is the entire session, and it ends before you have put the phone down.

Every entry also carries an example sentence, and that sentence is never spoken on the charger. It sits on the screen, on the phrase page, where you can read it and tap its own audio if you want to hear it. We keep it silent on the charger on purpose. Spoken, it would stretch a few seconds into a paragraph and bury the one word you were meant to catch; on screen it does its real job, which is showing the word in company.

All of the audio is text-to-speech; the Portuguese packs use a Brazilian voice.

One word is the right size for a plug-in

The charger is a trigger you already pull. Most people plug in at a desk, in a car, next to the bed, and each plug-in is a few seconds of attention that was about to go to nothing. A lesson does not fit in that gap. A lesson needs you to sit down, open something and decide to be a learner for a while, and those decisions are the ones that quietly stop happening.

One word fits the gap with room to spare. You hear it, you say it back in the pause if you feel like it, you put the phone down. The effort we removed is the scheduling, the streak and the daily decision to open an app. The word itself still has to be heard and said, because the words are the thing you are trying to remember.

Several plug-ins a day at one word each also adds up differently from a lesson. Spaced repetition wants many short meetings with a word spread across days, and a charger hands out short meetings spread across a day without anyone planning them. A long lesson delivers one meeting, and then the phone goes back in your pocket until you decide to have another.

How the sampler picks the word

Each entry in the pack you are learning carries a weight. The weight grows with the number of days since you last heard the entry, on a scale of five days: a word you heard this morning weighs very little, a word from last week weighs a good deal more. When you plug in, the app draws one entry at random with odds proportional to those weights. Nothing else goes into the draw. We call it a weighted decay sampler, and the plain-English version is that the app keeps bringing back what you are about to forget.

A word you have never heard gets a head start. The sampler counts an unheard entry as about twenty days overdue, which on a five-day scale makes it far heavier than anything you heard recently. So in the first days with a new pack the draws are dominated by words you have not met yet, and the pack introduces itself quickly. As the unheard pile shrinks the weights even out, and the rotation settles into revisits: yesterday's word competes with last week's, and last week's usually wins.

There is no quiz in the loop and nothing grades your answer. The sampler knows when a word was last played and nothing else, which keeps every plug-in free of taps. That choice has a cost, and it is described further down because it is real.

No streaks, and the app never asks you to open it

A streak is a promise to open an app every day, and a reminder is the app collecting on that promise. Both work for a while, and both make the learning depend on the one thing that runs out, which is your willingness to be nagged. Vocabcord has neither. Your record is the list of words you have heard and when, and the sampler reads that list; nothing on the screen counts days or asks you to come back.

The reason is the trigger. When the word rides the charger, the app has no need to summon you, because the charger summons the word. Skip a day and nothing breaks: the weights of the words you missed keep growing, and at the next plug-in the most overdue entry is the likeliest to come first.

Two optional extras exist for people who want more than the charger gives them. A daily word can arrive as a notification, read aloud if you turn that on, and the last word played sits on a lock-screen or home-screen widget so you can glance at it later. Both are opt-in; the charger alone is the method. There is also no account, and packs live on the phone and play offline.

The one-time Shortcuts step on iPhone

Apple does not let an app start itself when a charger is connected. The Shortcuts app can react to that event through what Apple calls a personal automation, so that is the route. On iOS the setup has one extra step: you create an automation once that runs Vocabcord when the charger connects, and from then on the phone does the rest. You do it once.

We would rather the step did not exist. It is the single point in the setup where a person can stop, and a plug-in automation is a strange thing to ask of someone who came for Spanish words. It is also the reason the method works on an iPhone at all. Without it, the app would have to rely on you opening it, which is the habit we built the whole thing to get away from.

Android needs none of this. The system lets an app listen for the charger directly, so on Android you install Vocabcord, choose a language and a level, and the next plug-in plays.

Where the words come from

The words are drawn from a corpus we built for the purpose: 33,233 entries across 617 packs, each entry a word or short headword with its translation and one example sentence in context. Six learner languages pair with English in both directions: Spanish, French, German, Italian, Portuguese and Polish. Every entry is graded A1 to C2 and tagged with a theme such as Food & Drink, Travel & Places or Everyday Verbs. An English-only B1 starter of 770 entries is free. Sizes differ by language: French and Polish are the smallest at 4,708 entries across both directions, Spanish sits at 4,710, and Portuguese is the largest at 5,960.

The word list underneath is derived from the New General Service List (NGSL 1.2, by Browne, Culligan and Phillips), published under CC BY-SA 4.0, and that is what lets us say that an A1 word is one you will hear often. Grading into levels, theme curation, the statistics and the audio are ours. The full method is on the methodology page, and the counts for every language and level are on the corpus statistics page.

Level matters more here than in a course, because the sampler treats every entry in a pack as equal and never asks whether a word was too hard. Start one level below where you think you are. A word you already know costs you a few seconds; a word far above you costs a plug-in you learned nothing from.

Where this is weak

The method teaches you to recognise a word when you hear it and to produce it when you need it, for single words and short phrases. It does not teach grammar or conversation, and we do not claim it does. The example sentence on the screen shows a word in company, and that is as far as the app goes toward building sentences. Pair it with something that makes you talk.

It also depends on a phone that gets charged during the day. If your phone charges once, overnight, you will hear one word a day, and one word a day is a slow way to learn a language. The people the method suits are the ones whose phone meets a cable at the desk, in the car and by the bed, and for them the day supplies the repetitions. For everyone else the honest number is small, and the daily notification adds one more word, which is still small.

The sampler has a blind spot we are not sure how to close. It knows when you last heard a word and nothing about whether you knew it, so a word you have known for years and a word you keep missing come back on the same curve. A self-graded quiz would fix that and would also put a decision on every plug-in, and we have not found a version of that decision that does not turn the word into a chore. For now we accept the blind spot and keep every plug-in tap-free.

If the open question for you is which level to start at, the frequency-first guide to Spanish vocabulary walks A1 to C2 and says what each level buys you.

Common questions

Does Vocabcord play a word every time I plug in my phone?

Yes. Each time the charger connects, one word plays: the target word, a pause, the translation, a pause, the target word again. On iPhone this runs through a Shortcuts personal automation you set up once; on Android the app reacts to the charger on its own. The example sentence for the word is shown on screen and is never spoken on the charger.

How does Vocabcord choose which word to play?

With a weighted decay sampler. Every entry's weight grows with the days since you last heard it, on a five-day scale, and the app draws one entry with odds proportional to those weights. A word you have never heard counts as about twenty days overdue, so new words dominate at first and the rotation evens out as the pack gets heard.

Why does Vocabcord need a Shortcuts automation on iPhone?

Apple does not let an app start itself when the charger connects. The Shortcuts app can react to that event through a personal automation, so Vocabcord uses that route: you set the automation up once and the phone runs it from then on. Android has no such rule, so the Android app listens for the charger directly.

Is one word per charge enough to learn a language?

It is enough to build and keep vocabulary if your phone gets plugged in several times a day, because each plug-in is one more spaced meeting with a word. It does not teach grammar or conversation, so pair it with something that does. If your phone charges only overnight, expect one word a day, which is slow.

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