Are humans capable of both anaerobic respiration, and lactic acid fermentation?

And if so, when do they do each?

I understand that the difference between respiration and fermentation is that respiration takes place in the electron transport chain.. I understand that aerobic respiration uses oxygen in the electron transport chain, and anaerobic respiration uses some other molecule in the electron transport chain instead of oxygen, like nitrate. Whereas fermentation doesn't use the electron transport chain at all.

I know humans have an anaerobic metabolic process that produces lactic acid, but i'm not clear whether it's respiration, or fermentation, or whether it could be either, in which case when it is which?

[the question has some good answers, but i've removed from the question some examples of conflicting definitions and some other stuff, that i'd added, as it may have made the question a bit hard for some people to read]