YouTube’s Automatic Closed-Captioning of Mathematical Speech (Part 2)

Last semester, as I spend untold hours editing the closed captioning automatically generated by YouTube on the math videos on my YouTube channel, I got a crash course on the capabilities and limitations of this system. This crash course was perhaps not legally necessary but extra work that I took on because a student with a hearing impairment was enrolled in my class, and I wanted to ensure that the review videos that I provide to my students were accessible to him also.

I think the resources offered by my university are fairly typical to ensure that instructors are able to reach all students and not just those who don’t have audio/visual impairments. After discussions with the cognizant people at my university, I’ve made a few conclusions:

  • Mostly by accident, my videos are ADA compliant since I made the decision to both write out the solutions and also talking through the solutions.
  • While the automatic closed-captioning provided by YouTube may be minimally compliant with ADA, I’m not sure that a student with a hearing impairment could always follow the transcriptions due to a number of errors.
  • Aside from punctuation, capitalization, and the occasional homonym (e.g., right vs. write), YouTube does a pretty good job at transcribing ordinary speech.
  • Naturally, YouTube’s automated closed-captioning is not to blame when I don’t enunciate clearly, have a rabbit trail of thought but then have to backtrack, use poor grammar, make a outright mistake, etc.
  • However, YouTube seems to have a lot of difficulty providing automatic closed-captioning of mathematical speech.

Fixing these transcription errors took an awful lot of time. I don’t want to know how many hours I devoted to fixing the 120 or so videos (each video is about 3-10 minutes long) recorded so that my hearing-impaired student could have full access to my class. About halfway into this project of fixing the closed-captioning errors, I started writing down some of the closed-captioning errors. I wish I had thought to do this near the start, but oh well.

Phonetically, I can understand why most of these errors were made. But these mistakes really shouldn’t have happened. Here are my favorite howlers that I recorded, showing both what I said and what YouTube thought I said.

  • “931,147,496” became “930 1,000,000 147,000 496”
  • A cap C,” pronounced “A intersect C,” became “A inner sexy”
  • “arithmetic” became “rhythm sick”
  • “capital X” became “Catholics”
  • “cardinality” became “carnality”
  • “divisible by 5” became “visited his wife live” (I have no idea how that happened)
  • e^x” became “eat ooh the x”
  • “for succinctness” became “force the sickness”
  • n choose n,” pronounced “n choose n,” became “and shoes and”
  • “set containing” became “second taining”
  • sqrt{2}” became “squirt tuna”
  • “two ways in” became “too wasted”
  • “what f(3)," pronounced "what latex f$ of 3,” became “whateva 3”
  • x in B, pronounced “x is in B,” became “sexism be”
  • x in B cap C, pronounced “x is in B and C,” became “x is Indiana see”
  • x in C, pronounced “x is in C,” became “excellency”

Here’s the complete list of howlers that I recorded for posterity. If I’ve learned nothing else, it’s that I need to be more proactive about ensuring the mathematical accuracy of closed-captioning for my YouTube videos.

4 for
857 a 50 7
1232 1230 two
4761 4760 1
19,999 19,000 999
46,376 40 6376
123,552 120 3,552
5,565,120 five million 565,000 120
931,147,496 930 1,000,000 147,000 496
(2,\emptyset) 2d sent
(20,8) 28
[1,2] one too
12 \choose 4 12 juice 4
16 \choose 8 16 choosing
3 + 1 = 4 surplus one mix for
4 \choose 0 4 2 0
4 \choose k four twos k
49 \choose 5 49 she’s 5
50 \choose 6 52 six
8 \choose 2 a choose to
A \cap C A inner sexy
A \cap D a intersecting
A \cup B a you be
A \cup C a UNC
A \cup C a you will see
a proof approved
A^c a compliment
a_i asa by
all multiples of almost visit
an element of A known the debate
an element of A normal today
and divisible and as above
and positive 50 + + 50
and tens intense
and would let this be 3 andrew lippa p3
arithmetic earth to
arithmetic rhythm sick
As ace
B but not C be but not si
B \cap C b in a sexy
B if beef
bijection bi CH action
bijection bite jection
bijection by dejection
bijection by ejection
bijection by jection
bijection by Junction
both sets both says
capital X Catholics
cardinality carnality
Cartesian car to shull
codomain code Amin
coordinate cordon
coordinate court
coordinates corners
coordinates have cort in sap
cosine cosign
disjoint destroyed
divisible by 5 visited his wife live
e^x eat ooh the x
element of A illness of A
element of A mellow today
element x that Windex
elements of us
empty MQ
\emptyset descent
\emptyset intercept
equal able
exponent x1
factored acted
factorial fact welders
fill in film
flipping four coins philippine for coins
for succinctness force the sickness
hence in Hanson
i eye
i aye
If I divide by 15 If I / 15
in A nae
in there a bear
infinite if an
infinite imp an
infinite infant
into five in 2 5
is ice
j \choose r j choose arms
kth cave
kth kate
likewise lakh wise
n \choose n and shoes and
nth row nth throw
one-to-one 121
onto on 2
r \choose r our shoes are
r to art at
r to already
\mathbb{R}^2 are too
\mathbb{R}^2 our too
r‘s hours
same row samro
second coordinate sec cornered
set containing second inning
set containing second taining
set containing seconds hanging
set containing secretary
set containing 1 second anyone
since A has say has
sixth one six-month
square swear
\sqrt{2} score 2
\sqrt{2} squirt of tuna
team A teammate
term in it terminate
than zero gloves are off
that’s chosen that’s Showzen
then x the next
therefore there for
this entry in the century plus
to the k decay
two are to are
two ways in too wasted
union you need
up here pier
what f(3) whateva 3
will be 4 will before
with n=4 finials 4
would subtract was attract
writing riding
x is extras
x is in exiting
x is in A x as a native
x is in A x is nay
x is in B sexism be
x is in B and C x is Indiana see
x is in C excellency
x is in C X’s and see
x_2 next to
x_2 text too
x-coordinate export
y why
y wine
y is greater than or wider
ys wise



My Favorite One-Liners: Index

I’m doing something that I should have done a long time ago: collecting a series of posts into one single post. The links below show my series on my favorite one-liners.

Mathematical Wisecracks for Almost Any Occasion: Part 2Part 7, Part 8, Part 12, Part 21, Part 28, Part 29, Part 41, Part 46, Part 53, Part 60, Part 63, Part 65, Part 71, Part 79, Part 84, Part 85, Part 100, Part 101Part 108, Part 109, Part 114

All-Purpose Anecdotes: Part 38, Part 50, Part 64, Part 70, Part 92, Part 94

Addressing Misconceptions: Part 3Part 4Part 11, Part 14, Part 15, Part 18, Part 30, Part 32, Part 33, Part 37, Part 45, Part 59

Tricky Steps in a Calculation: Part 5, Part 6

Greek alphabet and choice of variables: Part 40, Part 43, Part 56

Homework and exams: Part 39Part 47, Part 55, Part 57, Part 58, Part 66, Part 77, Part 78, Part 91, Part 96, Part 97, Part 107

Inequalities: Part 99

Simplification: Part 10, Part 102, Part 103

Polynomials: Part 19, Part 48, Part 49, Part 81, Part 90

Inverses: Part 16

Exponential and Logarithmic Functions: Part 1, Part 42, Part 68, Part 80, Part 110

Trigonometry: Part 9, Part 69, Part 76, Part 106

Complex numbers: Part 54, Part 67, Part 86, Part 112, Part 113

Sequences and Series: Part 20, Part 35, Part 111

Combinatorics: Part 27

Statistics: Part 22, Part 23, Part 36, Part 51, Part 52, Part 61, Part 95

Probability: Part 26, Part 31, Part 62, Part 93

Calculus: Part 24, Part 25, Part 72, Part 73, Part 74, Part 75, Part 83, Part 87, Part 88, Part 104

Logic and Proofs: Part 13, Part 17Part 34, Part 44, Part 89, Part 98

Differential Equations: Part 82, Part 105










Please curve my exam

Vertical line test


C is for constant of integration, and that’s good enough for me


Derivative of 1/x




Fibonacci joke




The Pythagorean theorem to five decimal places

Piers Morgan, mathematician extraordinaire:

I don’t know how to begin describing how his attempt at insulting the intelligence of one of the Love Island evictees went horribly wrong.

Greeting Cards for Scientists