ABSR	Assistant-based speech recognition
AED	Attention-based encoder–decoder
AM	Acoustic model
AMAN	Arrival manager
AP	Average pooling
ASR	Automatic speech recognition
ATC	Air traffic control
ATCos	Air traffic controllers
BERT	Bidirectional encoder representations from transformers
CER	Character error rate
CMVN	Cepstral mean and variance normalization
CNNs	Convolutional neural networks
CmdER	Command error rate
ConER	Concept error rate
CSA	Callsign accuracy
CTC	Connectionist temporal classification
DNN	Deep neural networks
E2E	End-to-end
FAA	Federal Aviation Administration
FBank	Filter bank
FC	Fully connected
GMM	Gaussian mixture model
HMM	Hidden Markov model
ICAO	International Civil Aviation Organization
LF-MMI	Lattice-free maximum mutual information
LM	Language model
LSTM	Long short-term memory
MCNN	Multiscale CNN
MFCC	Mel frequency cepstrum coefficient
MTPM	Machine translation PM
PLM	Phoneme-based LM
PM	Pronunciation model
PPR	Parallel phone recognition
RIA	Repetition intention accuracy
RNNs	Recurrent neural networks
RNN-T	Recurrent neural network transducer
RTF	Real-time factor
SER	Sentence error rate
STFT	Short-time Fourier transform
TDNN	Time delay neural network
VHF	Very high frequency
WER	Word error rate
WFST	Weighted finite-state transducer
WLM	Word-based language model