Frequent-word subsampling keep-probabilities that downweight very common words during training.
Generate (center, context) training pairs from a token sequence within a context window.
The unigram^0.75 noise distribution used to draw negative samples.
The skip-gram with negative sampling objective over a center, its positive context, and k negatives.
Continuous bag-of-words: average context vectors, project, and score the center word.
One full SGD step: forward, gradients for both embedding matrices, and the parameter update.