<s>
Speech	B-Algorithm
processing	I-Algorithm
is	O
the	O
study	O
of	O
speech	O
signals	O
and	O
the	O
processing	O
methods	O
of	O
signals	O
.	O
</s>
<s>
The	O
signals	O
are	O
usually	O
processed	O
in	O
a	O
digital	B-General_Concept
representation	O
,	O
so	O
speech	B-Algorithm
processing	I-Algorithm
can	O
be	O
regarded	O
as	O
a	O
special	O
case	O
of	O
digital	B-General_Concept
signal	I-General_Concept
processing	I-General_Concept
,	O
applied	O
to	O
speech	O
signals	O
.	O
</s>
<s>
Aspects	O
of	O
speech	B-Algorithm
processing	I-Algorithm
includes	O
the	O
acquisition	O
,	O
manipulation	O
,	O
storage	O
,	O
transfer	O
and	O
output	O
of	O
speech	O
signals	O
.	O
</s>
<s>
Different	O
speech	B-Algorithm
processing	I-Algorithm
tasks	O
include	O
speech	B-Application
recognition	I-Application
,	O
speech	B-Application
synthesis	I-Application
,	O
speaker	B-Application
diarization	I-Application
,	O
speech	B-Application
enhancement	I-Application
,	O
speaker	B-Application
recognition	I-Application
,	O
etc	O
.	O
</s>
<s>
Early	O
attempts	O
at	O
speech	B-Algorithm
processing	I-Algorithm
and	O
recognition	O
were	O
primarily	O
focused	O
on	O
understanding	O
a	O
handful	O
of	O
simple	O
phonetic	O
elements	O
such	O
as	O
vowels	O
.	O
</s>
<s>
Pioneering	O
works	O
in	O
field	O
of	O
speech	B-Application
recognition	I-Application
using	O
analysis	O
of	O
its	O
spectrum	O
were	O
reported	O
in	O
the	O
1940s	O
.	O
</s>
<s>
Linear	B-Algorithm
predictive	I-Algorithm
coding	I-Algorithm
(	O
LPC	O
)	O
,	O
a	O
speech	B-Algorithm
processing	I-Algorithm
algorithm	O
,	O
was	O
first	O
proposed	O
by	O
Fumitada	O
Itakura	O
of	O
Nagoya	O
University	O
and	O
Shuzo	O
Saito	O
of	O
Nippon	O
Telegraph	O
and	O
Telephone	O
(	O
NTT	O
)	O
in	O
1966	O
.	O
</s>
<s>
LPC	O
was	O
the	O
basis	O
for	O
voice-over-IP	B-Application
(	O
VoIP	B-Application
)	O
technology	O
,	O
as	O
well	O
as	O
speech	B-Application
synthesizer	I-Application
chips	O
,	O
such	O
as	O
the	O
Texas	B-Application
Instruments	I-Application
LPC	I-Application
Speech	I-Application
Chips	I-Application
used	O
in	O
the	O
Speak	B-Application
&	I-Application
Spell	I-Application
toys	O
from	O
1978	O
.	O
</s>
<s>
One	O
of	O
the	O
first	O
commercially	O
available	O
speech	B-Application
recognition	I-Application
products	O
was	O
Dragon	O
Dictate	O
,	O
released	O
in	O
1990	O
.	O
</s>
<s>
By	O
the	O
early	O
2000s	O
,	O
the	O
dominant	O
speech	B-Algorithm
processing	I-Algorithm
strategy	O
started	O
to	O
shift	O
away	O
from	O
Hidden	O
Markov	O
Models	O
towards	O
more	O
modern	O
neural	B-Architecture
networks	I-Architecture
and	O
deep	B-Algorithm
learning	I-Algorithm
.	O
</s>
<s>
An	O
artificial	B-Architecture
neural	I-Architecture
network	I-Architecture
(	O
ANN	O
)	O
is	O
based	O
on	O
a	O
collection	O
of	O
connected	O
units	O
or	O
nodes	O
called	O
artificial	B-Algorithm
neurons	I-Algorithm
,	O
which	O
loosely	O
model	O
the	O
neurons	O
in	O
a	O
biological	O
brain	O
.	O
</s>
<s>
Each	O
connection	O
,	O
like	O
the	O
synapses	B-Application
in	O
a	O
biological	O
brain	O
,	O
can	O
transmit	O
a	O
signal	O
from	O
one	O
artificial	B-Algorithm
neuron	I-Algorithm
to	O
another	O
.	O
</s>
<s>
An	O
artificial	B-Algorithm
neuron	I-Algorithm
that	O
receives	O
a	O
signal	O
can	O
process	O
it	O
and	O
then	O
signal	O
additional	O
artificial	B-Algorithm
neurons	I-Algorithm
connected	O
to	O
it	O
.	O
</s>
<s>
In	O
common	O
ANN	O
implementations	O
,	O
the	O
signal	O
at	O
a	O
connection	O
between	O
artificial	B-Algorithm
neurons	I-Algorithm
is	O
a	O
real	O
number	O
,	O
and	O
the	O
output	O
of	O
each	O
artificial	B-Algorithm
neuron	I-Algorithm
is	O
computed	O
by	O
some	O
non-linear	O
function	O
of	O
the	O
sum	O
of	O
its	O
inputs	O
.	O
</s>
