Text to Speech for Dyslexia: What Actually Helps

This question has a real answer, which is rarer than it should be in assistive-tech marketing. Wood, Moxley, Tighe and Wagner published a meta-analysis in the Journal of Learning Disabilities, "Does Use of Text-to-Speech and Related Read-Aloud Tools Improve Reading Comprehension for Students With Reading Disabilities?" (2018), pooling studies of TTS and read-aloud tools. The answer was yes, with a moderate average effect size of .35 on reading comprehension.

Two honest framings of that number. First, moderate is meaningful: it is the difference between a chapter that lands and a chapter that has to be reread. Second, TTS is assistive, not remedial. It does not teach decoding, and it is not a substitute for structured literacy instruction. What it does is decouple access to books from decoding speed, so a student can read at the level they think, not the level they decode.

If you take one feature requirement from this page, take this one. Reading with dyslexia often fails at tracking: losing the line, losing the word, spending effort re-finding your place that should have gone to meaning. Audio alone does not fix that. It just moves the text somewhere invisible.

Synced highlighting fixes it mechanically. When each word lights up the instant it is spoken, your eyes never have to find anything: the text finds you. Eyes and ears stay locked to the same word, every printed word arrives paired with its pronunciation, and a glance away costs nothing because the highlight marks the way back. LoudReader highlights the current sentence and the current word within it, on every book, with no setup.

• Word-level highlighting, not just sentence-level. The lock between eyes and ears happens at the word.
• No word quota. A novel is 80,000 to 120,000 words. Metered plans are priced for snippets, not for how dyslexic readers actually use TTS, cover to cover.
• A voice you can live with. Robotic voices add listening effort exactly where you are trying to remove reading effort. Natural offline voices matter for hours of daily use.
• Speed control, slower for dense material, faster once a voice is familiar.
• Your real reading, school PDFs, EPUB novels, not just pasted text boxes.

The dyslexia-TTS space is crowded, and the truthful comparison is more useful than a rigged one:

• Microsoft Immersive Reader is free and already inside Word, OneNote, Teams, and the Edge browser. Its Read Aloud highlights each word, and Line Focus and text spacing are genuinely good. If your reading lives in documents and web pages, start there, since it costs nothing. It is not, however, a home for a book library.
• Read&Write (Texthelp) owns classrooms: schools deploy it centrally, it integrates with learning platforms, and its TTS reads with dual-color highlighting. If your school provides it, use what you have.
• Speechify is the most heavily marketed option and its highlighting is word-for-word, but its free tier is 10 standard voices at up to 1.5x speed, and Premium is $29/month with a metered word allowance. For book-length listening, the meter is the wrong shape. The full comparison is in our Speechify alternative page.

LoudReader is built for exactly one of these jobs: whole books, read aloud, followed with your eyes. Word-by-word highlighting is free on every book, and free listening is unlimited: no word quota, no metered months, cover to cover. Voices are natural offline voices, and the app is fully on-device and private, your library never leaves your device, which also means a student's reading data isn't anyone's telemetry.

The honest limits: English only today; playback-speed control (0.3x to 3.0x) is a Premium feature, as are the extra voices after the 8-hour all-voices trial; and scanned PDFs without a text layer can't be read. If those are dealbreakers, the alternatives above are real options. If not, it is a free download, with no account and nothing to configure.