one mispronunciation that I hear often among very senior devotees is in Srila Prabhupada's pranati.


namas te sārasvate deve gaura-vāṇī-pracāriṇe
nirviśeṣa-śūnyavādi-pāścātya-deśa-tāriṇe

although devotees say pracharine in the first line in the second line they say pashKatya

I think a lot old kirtan recording also pronounce it in that way as well.

in the Nrisimha prayers in kirtan one thing that I noticed myself and a lot of other devotee doing is when singing;


ito nrisimhah parato nrisimho
yato yato yami tato nrisimhah
bahir nrisimho hridaye nrisimho
nrisimham adim sharanam prapadye

on the last line a lot of devotees (I caught myself doing it) chant Narasimham adim sharanam prapadye

i don't know, but it is the lyrics of the prayer

The Visnu’s name was Sri Mädhava, which means “husband of the goddess of fortune,” but I mistakenly copied it on the painting as “SRI MADAAVA.” Prabhupäda pointed out my mistake. He calmly said he had written MAD-HAVA—with an “H.” But I couldn’t accept that I had made the mistake.
“No,” I said, “you wrote an A.”
We went back and forth:
“A!”
“H!”
“A!”
“H!”
I eventually realized how foolish I was to argue with my spiritual master. Not only did he know Sanskrit, which I didn’t, but he had perfect knowledge of everything. Naturally, Prabhupäda was right. And when I came to learn a little Sanskrit, I understood that it could not have been “MADAAVA.”
Several devotees were in Prabhupäda's room when I presented him the finished work.
“Now, who cannot look at that and say it is not God!” Prabhupäda announced, and all of the devotees cheered.
“It is beautiful,” I thought. “I don’t know if I can ever do one that good again, but I sure will try.”
The unfortunate fact, however, was that technically the painting was terrible, but with Prabhupäda's encouraging words I was able to continue trying to render him service. Had I not received so much encouragement, I might have stopped. But Prabhupäda was confident that Krsna would carry what his disciples lacked.

CC 3.16.52-53, attributed to Nrsimha Purana.

The differences stem from variations in transliteration standards and limited knowledge of sanskrit pronunciation. The BBT has also used two different transliterated versions of Nrsimha. (I would post them here but I can't get the copy and pasting of diacritics to work. Sorry.)

For the 'r' in the original question:
The 'r' in Nrsimha is an 'r' with a dot under it, which means the tongue is curled to the back of the roof of the mouth when pronounced. There is no single english equivalent. When transliterating without using diacritics, the nearest english equivalent sound is simply 'r'.

For the 'a':
There are two options for transliterating the short 'a'.
1. Don't put the 'a.' The reason for this is that any whenever you say any consonant, a short 'a' sound is automatically produced. In this case, Nrsimha is correct.
2. Put the a. In this case, Narasimha is correct.
But for both options, the reader should know that the 'a' is short (not the long 'ā') and should hardly be pronounced at all.

For the simha and singha:
The actual sanskrit sound is 'm' with a dot on the top, which also doesn't have an equivalent english sound and is purely nasal. When transliterating without using diacritics, the nearest english sound is 'ng' and the next nearest equivalent is an english 'm'. Hence the two versions.

So the following are all acceptable ways of transliterating without using diacritics :
nrsimha
nrsingha
narasingha
narasimha

Hope this helps.

VEDA:

It's a mispronunciation of NiSAzRNga, one of His names. Similar ones: MahAzRNga, EkazRNga, DvizRNga, BahuzRNga, HiraNyazRNga, ZRNgI.

Where can I find a list of Lord Nrsimha's name?