Obviously Shark species would have different common names in another language.   If we spoke Spanish a mako would be marrajo dientuso, the blue would be tiburon azul.   Now multiply this by hundreds of different languages and dialects, and that's why we have common name chaos, worldwide.

From one geographical area to another, even within the same country, we use more than one common name in the same language to describe the same shark species.  

One man's mako is another man's bonito shark.   One man's smalleye hammerhead is another man's golden hammerhead.  On Cape Cod the sandbar shark, Carcharhinus plumbeus, is called the "brown shark".   The better known sharks usually have several common names in the same language throughout the world.  Some sharks are so rare they lack any common name, having only a scientific name." 

Several shark species have confusing similar sounding common names like: Sandbar, Tiger, Sand Tiger.  
These are three distinct and very different species:  the often caught from the beach, medium sized  Sandbar (Carcharhinus plumbeus, also known as the brown shark) the very big and dangerous Tiger, Galeocerdo cuvier and the very toothy and finny Sand Tiger, Carcharias taurus.  (I say finny because both dorsals, and the pelvic and anal fins on the sand tiger are close to being the same size.)

In some instances a singular common name is applied to several species.  For example, in different localities along the East Coast; the dogfishes, Squalus acanthias, sandbar sharks, Carcharhinus plumbeus, and sand tigers, Carcharias taurus, are all called “sand sharks,” even though they are three separate species, and there really is no sand shark species. Although 50 or so years ago, Carcharias taurus was called the sand shark, but now is called the sand tiger.

Of course we are all going to still use  common names for sharks but we should be aware there is another method less ambiguous.  That is using scientific names. 

To people who are knowledgeable about roses, it is a meaningless statement, since they are familiar with so many species of roses they may not know what kind of a rose to visualize. So just saying rose doesn’t mean anything specific to them. Roses, like sharks, come in all kinds of colors, sizes and shapes. Knowledgeable rose people may want more detailed information to know what  type or species of rose you are talking about. 

As you learn more about a subject you want more specifics to avoid confusion-and that applies to sharks. Discussing sharks can get very confusing. You or I might describe certain shark species as; shortfin mako, bull shark and salmon shark. Others will describe those same species as; bonito shark, Zambezi shark and Pacific porbeagle. Obviously there is a problem. It is common name confusion. It exists in all languages- more than one common name for the same species.

In 1758, a Swedish botanist, Carl von Linne’  popularized  a binomial system to classify  the various species, including sharks of course. There were other systems in place for hundreds of years prior to this but they never got widespread acceptance,  Carl von Linne made the binomial system  popular. 

 This helped bring some order to an otherwise chaotic situation.  In that period of time many learned people corresponded in Latin. There were scientists at that time who used as many a nine Latin/Greek/other words to describe a species.  

By choosing a two part Latinized and/or  Greek name to describe the various species,  it simplified scientific name designations.    By using  Latin/Greek, it didn't offend anyone's language sensibilities.   Carl von Linne’s name was  latinized to Carolus Linnaeus.  

(I  can't help but notice that some taxonomists seem to want to go back to the multiple word species designation such as calling the dog,  by 3 scientific names, Canis lupus familiarus, or by calling a particular breed of dog like the Hungarian wavy coated dog by 4 scientific names, Canis familiarus undulans hungaricus. Or calling a grizzly bear (Ursus arctos)  as Ursus arctos horribilis.
(The polar bear is Ursus maritimus which means sea bear.)

And when I say they use Latin/Greek for scientific names, don't expect a direct translation from a Latin or Greek dictionary to clarify the meaning. 

Also many of the two words used to describe a shark species may have Greek origins; which get mongrelized by getting latinized. As an example, the shortfin mako, Isurus oxyrinchus , both of the scientific names are Greek; an approximate meaning would be:  equal tailed with a sharp snout.

And if a species is named after a person or a geographical location the  name may be Latinized.  

If you know Latin or Greek, don't expect to look at  the scientific name, and bet you can figure it out.   You might be able to do it in some cases if you know the Latin and Greek roots, but in some of the mongrelized scientific names you won't. 

  

Taxonomy, is the science of classification.  It would be convenient if the assigned latinized names stayed the same through the years, but they don't.  Scientific name changes are always occurring.  Unlike some groups, scientists do not ignore new evidence that refutes previous held beliefs. They make the changes no matter how inconvenient.  

Recently the sandtiger, Carcharias taurus had its scientific name changed to Eugomphodus taurus, then to Odontaspis taurus and presently back to Carcharias taurus.  

Sometimes the changes to scientific names are minor, like changing the spelling of one of the latinized words, such as changing the Genus spelling of the whale shark, from Rhiniodon typus to Rhincodon typus; or changing the species designation spelling of the tiger from  Galeocerdo cuvieri, to Galeocerdo cuvier. 

Worldwide common sharks familiar to the scientists such as the blue ,mako, white, and common thresher have undergone dozens of scientific name changes through the centuries.  One of the many examples is the Basking shark, Cetorhinus maximus; it has had at least twenty scientific name changes. Those changes are made on the basis of new data; and are dependent on peer review of the scientific community.   It takes about 10 years for a new scientific name or idea to become mainstream. 

Who classifies the shark species?

Dr. Leonard J.V.Compagno for the United Nations Food and Agriculture Organization (FAO)  puts out a shark species catalogue.  Those shark classifications are accepted by most biologists.  There are other biologists and taxonomists that probably would classify differently.  But his classifications are the ones most widely used. And are the ones I go by.

An example of a change in classification for us avid striper fishermen, is our well known and loved striped bass.  The striper was classified years ago as Roccus saxatilis, and is now classified as Morone saxatilis. 
(My wife thinks the new striper classification Morone is more appropriate for us morons who spend a great deal of our time in quest of the striped bass, while our houses and family relationships fall apart around us.)

A problem with gathering information on sharks is that they are cartilaginous, without rib cages, with very little if any bone in their bodies.  So there aren't any fossilized bony skeletons with rib cages to analyze.  Only shark teeth survive, or a few fossilized impressions. 

Recreational anglers participating in shark tagging have helped in some areas of shark study; especially migratory patterns, and  age /growth studies.

I will give you a couple of examples of how gathering shark information has been a slow process. This is not a criticism of the work of the biologists; it's a big ocean, and the number of scientists working on sharks has always been small, increasing somewhat in recent years, and no doubt being helped by new technology. And also being helped by them getting off their asses and getting out of the lab and onto the water.   (Just recently, I was at a seminar and a young female biologist summed it up about the same,  when one of her slides said. "What we need is more marine biologists peeing in the ocean.")  

Our New England porbeagle, Lamna nasus,   was classified in 1788, but its relative, the West Coast salmon shark, Lamna ditropis, wasn't classified as a separate species until 1947, a passage of 159 years. 

The shortfin mako, Isurus oxyrinchus was classified in 1810, but the longfin mako , Isurus paucus, wasn't classified until 1966.  

In the past, the dangerous salt and freshwater going bull shark, Carcharhinus leucas,   was thought to be several different shark species.  

The Lake Nicaragua shark,  the Zambezi shark,  are in fact bull sharks and not separate species as was implied in the past. The bull shark was know by several other names also. 

The plankton eating Megamouth shark, Megachasma pelagios,  was not known to exist until an accidental capture of one in 1976.  Since that time a total of 37  megamouths have been discovered.   Incredible that a shark species that may reach 20  feet in overall  length, was not documented until 1976. 

A lot of the older literature on sharks contains inaccuracies, omissions,  exaggerations, and has missed many of the existing species. Many of the so-called shark experts of the past knew very little about sharks compared to today's biologists.  
During the July, 1916 shark attacks off New Jersey, where 4 people were killed and 1 seriously injured, the statements to the newspapers made by so called credentialed experts about sharks were naive and ridiculous.

Because of the abundance of new information gathered in the last few years on sharks; Read the latest literature, and get it from  a reliable source.   I'll recommend some good shark books to read later in the web page.   Shark taxonomy (classification) is an ongoing process.