Deep where it counts.
Laesi has a lot of features. Most of the time you'll use a handful. The rest are there the day you need them — start with the core, grow into the power tools.
What you'll use every day
Import something to read. Click words you don't know. Set how well you know them. Export the keepers to Anki. That's it — everything else is optional depth.
Reader with knowledge highlighting
Paste text or open a book and every word is colored by how well you know it — Seen, Recognized, Remembered, Known. The page visibly clears as you learn.
Import books & subtitles + Library
EPUB and TXT for books, SRT and VTT for subtitles — plus MOBI, AZW3, DOCX, ASS, and SSA also supported. Read with page-style pagination, per-chapter navigation, and coverage stats.
Dictionary panel
Click any new word while reading to lemmatize it and pull definitions from Wiktionary or Google Translate — without leaving the page. Save only the senses you need.
Multi-word lemmas
Shift-click or drag to select phrasal verbs, idioms, and collocations. Save them as one entry with its own knowledge level and lookup.
Anki export
Queue words while reading, then export tab-separated cards in L2→L1, L1→L2, and cloze formats that match your existing decks.
Bulk actions
Mark a whole page known or seen. Ignore names and misspellings. Select all matching words and tag or queue them in one pass.
Grammar & POS tags
Saved definitions can carry a morphology summary (genitive singular, present 3rd singular…) and part-of-speech tags applied automatically on lookup.
Statistics
Track vocabulary by level, words read, and Anki exports — per language, over time.
Runs 100% locally
A native desktop app. Your vocabulary, texts, and progress live on your computer in a plain SQLite file — never on a server we can turn off.
Real lemmatizers, not surface-form lookup
Most reader apps fall back to matching the raw word you clicked. For morphology-heavy languages that breaks — kirja, kirjan, and kirjoissa become three separate "words."
Laesi routes each language through the best open analyzer available, so inflected forms collapse back to one dictionary entry.
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01
VoikkoReference-grade Finnish analysis — all 15 cases, consonant gradation, compound splitting.
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02
spaCyFull morphology for most modern European languages: Germanic, Romance, Slavic, Baltic, Greek, Maltese.
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03
GiellaLTFinite-state analyzers for the Sámi family, Faroese, Irish, Old Norse, Kalaallisut, and Central Ojibwa — with sentence-context disambiguation.
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Wiktionary surface fallbackAny language without a dedicated analyzer still works via direct Wiktionary lookup — and we keep wiring up new analyzers over time.
There when you want them
You don't have to touch any of this to get value out of Laesi. But it's all there — and for serious readers, it's the difference.
Browser extension (Chrome + Firefox)
Highlight words on any web page using your local vocabulary. Click a word to set its level, run a Wiktionary/Google lookup, or translate the surrounding sentence — bulk 'mark all seen/known' and a Record-Reading button included.
AI Graded Reader
Generate a graded version of any chapter — personalized to the words you already know, or to a CEFR level (A1–C1). Paste the model's response back in and Laesi stores it as an overlay you can read.
AI translate & annotate
Build a translate-and-annotate prompt for a chapter, run it in your LLM of choice, and paste the result back. Laesi turns it into an interlinear overlay and queues new lemmas for review — no API key wired in, fully paste-based.
Interlinear & Facsimile readers
Read with per-word glosses inline, or read scanned page images with tappable word blocks positioned over the original layout.
Custom languages
Add languages outside the catalog — minority dialects, conlangs, niche historical varieties. Laesi allocates a private-use code, validates your analyzer references, and walks you through setup.
Activation Wizard & Model Manager
Configure dictionaries, lemmatizer, and grammar-tag categories before a language goes live. Download analyzer models in-app with live progress — no command line for most languages.
Per-language settings
Reorder dictionary sources, pick a preferred lemmatizer, seed grammar-tag categories, and tune highlighting per language — including 3-way highlight / underline / off controls.
Multiple profiles
Share one install across a household, or keep separate vocabularies for different goals. Each profile is its own database — words, books, stats, and tags — with no passwords. Export, import, and merge them freely.
One app. Every tool. One price.
All of it included — $99 once, Mac, Windows, and Linux.