SpeSSies instead of speSHies (species). So common, even among those who should know better that the proper SH sound is rarely heard. There is a rule here (at least in American): C’s before i or e-led vowel combinations are almost always pronounced as sh. That might sound complex, but it is not. E.g. no one would not say O-SUN (for ocean) no one says SPESS-EE-AL for special. You will hear, however, negoSeate and contraverSeal instead of negoSHeate or controverSHal (four syllables, not fi-ive) from overly-miseducated types who think that they are being somehow “refined”. Similarly, no one says soSEEal for social, but the supposedly edumacated will say soSEEology all day long.

Also, my nominee for most “Misspelled and Never-Corrected” word in English, is the noun “marshal”, as in field marshal, fire marshal, parade grand marshal, US Marshal, etc. The misspelling of a doubled L on the end is this common– out of 5 academic-press books on my shelf right now on the subject of law and law enforcement it is spelled wrong in 3. Likewise I regularly encounter military literature populated with Field Marshalls (not the German kind). This is not a US-UK thing. I have the program for commencement from a well-regarded university with the Grand Marshall of the ceremony grandly announced on Page Three (or threee). The surname Marshall is almost always spelled so. That, probably, is a source of the confusion. But it’s no excuse. We don’t see mens’ taylor shops very often.