The categorization of texts into organized groups, which is usually implemented by supervised learning.
Applications: sentiment analysis, spam detection, news categorization, topic analysis, and more.

Text Classification

The pre-training and fine-tuning paradigm is a method motivated by the goal of creating adaptable, general-purpose systems for universal language understanding and generation. It involves separating the common components of neural network architectures, such as Transformers, and training them on vast amounts of unlabeled data using self-supervision. The resulting systems, known as foundation models, can be easily adapted for specific downstream applications via fine-tuning or prompting. This paradigm shift has enormously transformed natural language processing, meaning that in many cases, large-scale supervised learning for specific tasks is no longer required.

The Pre-training and Fine-tuning Paradigm

Different frequencies of sound waves are associated with differences in the perception of pitch. Low-frequency sounds correspond to lower pitched sounds, and high-frequency sounds correspond to higher pitched sounds.

Pitch and Frequency Relationship

The ability to perceive pitch relies on the activity of hair cells located in the basilar membrane. Specifically, it depends on both the firing rate of these hair cells and their physical location within the membrane.

Role of Hair Cells in Pitch Perception

The pitch of a sound is the mental sensation, or perceptual correlate, of fundamental frequency.

University of Michigan - Ann Arbor

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Phonology / Phonetics

An on-going but a helpful book resource about NLP
https://web.stanford.edu/~jurafsky/slp3/

Speech and Language Processing (3rd ed. draft) 

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020, April 22). Psychology (2nd ed.). OpenStax. https://openstax.org/books/psychology-2e/pages/1-introduction

OpenStax Psychology (2nd ed.) Textbook

How speech sounds are produced in the human vocal tract,
How speech sounds are realized acoustically,
How speech sounds can be digitalized and processed

Major Questions of Phonetics

The frequency of the vocal fold vibration.

Fundamental Frequency

$RMS \, amplitude_{i=1}^N = \sqrt{\frac{1}{N} \sum_{i=1}^N x_i^2}$

RMS Amplitude

Power of the Signal

Pitch

 A mel is a unit of pitch defined such that pairs of sounds which are perceptually equidistant in pitch are separated by an equal number of mels.

Phonetic Resources

The perceived loudness of a sound is directly related to the amplitude of its sound wave. Waves with higher amplitudes are interpreted as louder sounds, while those with lower amplitudes are perceived as quieter. This perceptual quality is measured using a logarithmic unit of sound intensity called decibels (dB).

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