Nerd Dictation

Offline Speech to Text for Desktop Linux. - See demo video.

This is a utility that provides simple access speech to text for using in Linux without being tied to a desktop environment.

Simple

This is a single file Python script with minimal dependencies.

Hackable

User configuration lets you manipulate text using Python string operations.

Zero Overhead

As this relies on manual activation there are no background processes.

Dictation is accessed manually with begin/end commands.

This uses the excellent vosk-api.

Usage

It is suggested to bind begin/end/cancel to shortcut keys.

nerd-dictation begin

nerd-dictation end

For details on how this can be used, see: nerd-dictation --help and nerd-dictation begin --help.

Features

Specific features include:

Numbers as Digits

Optional conversion from numbers to digits.

So Three million five hundred and sixty second becomes 3,000,562nd.

A series of numbers (such as reciting a phone number) is also supported.

So Two four six eight becomes 2,468.

Time Out

Optionally end speech to text early when no speech is detected for a given number of seconds. (without an explicit call to end which is otherwise required).

Output Type

Output can simulate keystroke events (default) or simply print to the standard output.

User Configuration Script

User configuration is just a Python script which can be used to manipulate text using Python's full feature set.

See nerd-dictation begin --help for details on how to access these options.

Dependencies

• Python 3.
• The VOSK-API.
• parec command (for recording from pulse-audio).
• xdotool command to simulate keyboard input.

Install

pip3 install vosk
git clone https://github.com/ideasman42/nerd-dictation.git
cd nerd-dictation
wget https://alphacephei.com/kaldi/models/vosk-model-small-en-us-0.15.zip
unzip vosk-model-small-en-us-0.15.zip
mv vosk-model-small-en-us-0.15 model

To test dictation:

./nerd-dictation begin --vosk-model-dir=./model &
# Start speaking.
./nerd-dictation end

• Reminder that it's up to you to bind begin/end/cancel to actions you can easily access (typically key shortcuts).

• To avoid having to pass the --vosk-model-dir argument, copy the model to the default path:

  mkdir -p ~/.config/nerd-dictation
  mv ./model ~/.config/nerd-dictation

Configuration

This is an example of a trivial configuration file which simply makes the input text uppercase.

# ~/.config/nerd-dictation/nerd-dictation.py
def nerd_dictation_process(text):
    return text.upper()

A more comprehensive configuration is included in the examples/ directory.

Hints

• The processing function can be used to implement your own actions using keywords of your choice. Simply return a blank string if you have implemented your own text handling.
• Context sensitive actions can be implemented using command line utilities to access the active window.

Paths

Local Configuration

~/.config/nerd-dictation/nerd-dictation.py

Language Model

~/.config/nerd-dictation/model

Note that --vosk-model-dir=PATH can be used to override the default.

Command Line Arguments

Output of nerd-dictation --help

usage:

nerd-dictation [-h]  ...

This is a utility that activates text to speech in Linux. While it could use any system currently it uses the VOSK-API.

positional arguments:

begin:	Begin dictation.
end:	End dictation.
cancel:	Cancel dictation.

optional arguments:

-h, --help

show this help message and exit

Subcommand: begin

usage:

nerd-dictation begin [-h] [--cookie FILE_PATH] [--vosk-model-dir DIR]
                     [--pulse-device-name IDENTIFIER]
                     [--sample-rate HZ] [--defer-output] [--continuous]
                     [--timeout SECONDS] [--idle-time SECONDS]
                     [--delay-exit SECONDS]
                     [--punctuate-from-previous-timeout SECONDS]
                     [--full-sentence] [--numbers-as-digits]
                     [--numbers-use-separator] [--output OUTPUT_METHOD]
                     [- ...]

This creates the directory used to store internal data, so other commands such as sync can be performed.

optional arguments:

-h, --help	show this help message and exit
--cookie FILE_PATH
	Location for writing a temporary cookie (this file is monitored to begin/end dictation).
--vosk-model-dir DIR
	Path to the VOSK model, see: https://alphacephei.com/vosk/models
--pulse-device-name IDENTIFIER
	The name of the pulse-audio device to use for recording. See the output of "pactl list sources" to find device names (using the identifier following "Name:").
--sample-rate HZ
	The sample rate to use for recording (in Hz). Defaults to 44100.
--defer-output	When enabled, output is deferred until exiting. This prevents text being typed during speech (implied with --output=STDOUT)
--continuous	Enable this option, when you intend to keep the dictation process enabled for extended periods of time. without this enabled, the entirety of this dictation session will be processed on every update. Only used when --defer-output is disabled.
--timeout SECONDS
	Time out recording when no speech is processed for the time in seconds. This can be used to avoid having to explicitly exit (zero disables).
--idle-time SECONDS
	Time to idle between processing audio from the recording. Setting to zero is the most responsive at the cost of high CPU usage. The default value is 0.1 (processing 10 times a second), which is quite responsive in practice (the maximum value is clamped to 0.5)
--delay-exit SECONDS
	The time to continue running after an exit request. this can be useful so "push to talk" setups can be released while you finish speaking (zero disables).
--punctuate-from-previous-timeout SECONDS
	The time-out in seconds for detecting the state of dictation from the previous recording, this can be useful so punctuation it is added before entering the dictation(zero disables).
--full-sentence
	Capitalize the first character. This is also used to add either a comma or a full stop when dictation is performed under the --punctuate-from-previous-timeout value.
--numbers-as-digits
	Convert numbers into digits instead of using whole words.
--numbers-use-separator
	Use a comma separators for numbers.
--output OUTPUT_METHOD
	Method used to at put the result of speech to text. SIMULATE_INPUT simulate keystrokes (default). STDOUT print the result to the standard output. Be sure only to handle text from the standard output as the standard error may be used for reporting any problems that occur.

- ... End argument parsing.

This can be used for user defined arguments which configuration scripts may read from the sys.argv.

Subcommand: end

usage:

nerd-dictation end [-h] [--cookie FILE_PATH]

This ends dictation, causing the text to be typed in.

optional arguments:

-h, --help	show this help message and exit
--cookie FILE_PATH
	Location for writing a temporary cookie (this file is monitored to begin/end dictation).

Subcommand: cancel

usage:

nerd-dictation cancel [-h] [--cookie FILE_PATH]

This cancels dictation.

optional arguments:

-h, --help	show this help message and exit
--cookie FILE_PATH
	Location for writing a temporary cookie (this file is monitored to begin/end dictation).

Details

• Typing in results will never press enter/return.
• Pulse audio is used for recording.
• Recording and speech to text a performed in parallel.

Examples

Store the result of speech to text as a variable in the shell:

SPEECH="$(nerd-dictation begin --timeout=1.0 --output=STDOUT)"

Example Configurations

These are example configurations you may use as a reference.

• Word Replacement.
• Start/Finish Commands.

Other Software

• Elograf - nerd-dictation GUI front-end that runs as a tray icon.

Limitations

• Text from VOSK is all lower-case, while the user configuration can be used to set the case of common words like I this isn't very convenient (see the example configuration for details).

• For some users the delay in start up may be noticeable on systems with slower hard disks especially when running for the 1st time (a cold start).

  This is a limitation with the choice not to use a service that runs in the background. Recording begins before any the speech-to-text components are loaded to mitigate this problem.

Further Work

• And a general solution to capitalize words (proper nouns for example).
• Wayland support (this should be quite simple to support and mainly relies on a replacement for xdotool).
• Add a setup.py for easy installation on uses systems.
• Possibly other speech to text engines (only if they provide some significant benefits).
• Possibly support Windows & macOS.