22 extensions tested, 4 Chrome-only exclusions documented, and an answer to "is NaturalReader worth $20/month?" (No.)
\frac{x^2}{2} as "backslash frac open brace x caret two..." -- useless.
FIX MathJax's built-in accessibility (right-click equation > Speech > Auto Voicing) works on MathJax sites with zero setup. For full articles: Smart TTS Reader converts LaTeX to spoken math via AI, but requires server setup. Paper2Audio summarizes equations in plain English.
reader.parse-on-load.force-enabled to true in about:config. Or prefix any URL with about:reader?url=. Read Aloud and Clearly Reader have their own content parsers that bypass Reader Mode entirely.
| Extension | Rating | Users | Updated | Price | TTS Engine | Outside Reader? | Selected Text? | LaTeX? | Notes |
|---|
The power user's TTS extension. Only Firefox extension connecting to multiple premium cloud TTS engines while remaining free. 217K+ users, actively maintained, open source (GPL v3).
Only actively maintained Firefox extension combining custom reader mode + TTS + LaTeX math rendering in one package.
The ONLY Firefox extension that explicitly converts LaTeX/MathJax to spoken math using AI preprocessing.
\sum_{i=1}^n x_i^2 becomes "sum from i equals one to n of x sub i squared"Purpose-built for academic papers, intelligently handles math by summarizing rather than reading symbols.
Purpose-built for academic papers with Firefox extension support. The most affordable paid option.
The Core Problem: Most TTS engines treat LaTeX as text. \frac{x^2}{2} becomes "backslash frac open brace x caret two close brace open brace two close brace" -- completely useless.
On any website using MathJax (arXiv, Stack Exchange, many academic sites):
Supports: ClearSpeak and MathSpeak rule sets, 12+ languages
Limitations: Only works on MathJax sites (not KaTeX or static images). Must interact with each equation individually. Uses basic browser voices.
Uses Gemini/Ollama AI to preprocess LaTeX into spoken English before TTS.
Example: \sum_{i=1}^n x_i^2 → "sum from i equals one to n of x sub i squared"
Requires: Gemini API key OR local Ollama + external TTS server (e.g., Kokoro-FastAPI)
Best for: Power users comfortable running local AI services who need precise math reading.
Summarizes equations in plain language rather than reading symbols. Good for getting the gist of papers, not for precise math.
Example: Instead of reading a complex integral, says "this equation represents the probability distribution over..."
Best for: Casual academic paper consumption where understanding > precision.
Option A: about:config → set reader.parse-on-load.force-enabled to true
Option B: Prefix URL: about:reader?url=https://...
Option C: "Activate Reader View" extension (7,759 users, 4.2/5)
Option D: Clearly Reader has its own parser independent of Firefox
System Settings > Accessibility > Spoken Content > "Speak selection"
Shortcut: Option + Esc on any selected text. Works system-wide in Firefox.
Download "Premium" voices (e.g., Zoe) -- significantly better than defaults. Free, 1-3GB each.
Limitation: Manual text selection only, no highlighting, no LaTeX.
Speechify (macOS app): $139/yr, 200+ voices, works with any app including Firefox. Won Apple Design Award 2025.
Piper TTS (local, open source): Fast neural TTS, runs offline on Apple Silicon. Free, unlimited. Requires CLI setup.
WebSpeakable (Tampermonkey): Select text, press 'P' to speak. Uses OS voices.
Verdict: No advantage over browser extensions. Same Web Speech API underneath.
That's the Plus plan at $19/mo (or $110/year annual). Short answer: no. Read Aloud + Google Cloud WaveNet free tier gives comparable voice quality at $0. If you want to pay, Listening.com at $39/year is 73% cheaper and purpose-built for papers.
| Engine | Quality | Cost | Offline? | Notes |
|---|---|---|---|---|
| ElevenLabs | ★★★★★ | $50/yr | No | Best-in-class but no working Firefox extension |
| Google WaveNet | ★★★★☆ | Free tier | No | 1M chars/mo free via Read Aloud |
| Amazon Polly Neural | ★★★★☆ | Free tier (12mo) | No | 1M neural chars/mo free via Read Aloud |
| NaturalReader Plus | ★★★★☆ | $110/yr | No | Marginally better than WaveNet |
| Speechify | ★★★★☆ | $139/yr | No | 200+ voices, macOS app only |
| Microsoft AI TTS | ★★★☆☆ | Free (Clearly Reader) | No | Used by Clearly Reader and MS Edge TTS |
| Piper (local neural) | ★★★☆☆ | Free | Yes | Best offline option, via Read Aloud |
| Kokoro AI (offline) | ★★★☆☆ | Free | Yes | ~300MB download, good quality |
| macOS Premium Voices | ★★★☆☆ | Free | Yes | 1-3GB per voice, decent quality |
| Browser Web Speech API | ★★☆☆☆ | Free | Yes | Varies by OS/browser, often robotic |