This is a very interesting question and opens other questions as well. There are many words in different languages that sound similar or even the same.  The wonderful answers of the other tutors give examples of languages using only the Latin alphabet.

 One look at the Slavic languages. For example the word "heart" in all Slavic languages sounds almost the same.  Several examples:

Bulgarian - surce, Macedonian - srce, Russian - serdce, Czech - srdce, Croatian - srce, Serbian - srce, Slovac - srdce, Slovenian - srce, Polish - serce. 

Notice that they use two different alphabets - Cyrillic and Latin, but the word sounds so similar in the different languages!  (The site does not use Cyrillic, so I cannot write the words with the right letters here, sorry.)  Back in the time when tribes were travelling from a place to another place, they were very often sharing land, and respectively - words, customs, culture...  Geographically close, they developed many similar things together.

Languages that have a common Latin root, share words, too, as the tutors before me wrote.  

But how about some words that sound very similar in languages that don't have anything in common, like the word "no" , for example? One can find more than 30 languages (from different Language families) in which the word "no" sounds so similar, or at least starts with the sound "n"!  Including Japanese. (But excluding Greek in which the word "no" is pretty exotic "ohi" (oxi).)

Languages borrow words from one-another.  Words like "computer" and "Internet" cross language barriers and don't need translation in any language. As the world is getting smaller, and people are travelling everywhere, more words get accepted in different languages.

Languages are fascinating!  There is a saying: "One lives as many lives as many languages one speaks."

 

Many words stem from Latin, and they will be very similar in sound, spelling, and pronunciation.  French, Spanish, and English fall into this particular situation.  Plus, as time changes, so do words.  There are more  words put into the English dictionary every year, and many of them stemming from another language.

All of these tutors hit it on the nose: Our origin in language stems from simply a few sources and have exploded onto the world stage with only some major permutations.

A lot of languages will 'share' words and phrases because of geographical promixity, but this isn't always the case. We wonder, then, how do they continue to share words and phrases in the absence of closeness? The answer then becomes 'geopolitical' proximity - this is what KEEPS those words and phrases  from morphing beyond recognition.

The term 'geopolitcal proximity' can be a bit misleading: 'Closeness' in geography is not equivalent to 'closeness' in political structures, which span a much wider area and indeed touch larger parts of the world. Looking at a 'political' map, the nations look a lot closer together and appear joined by common ideas (Unfortunately, this isn't ALWAYS the case). What all this means is that whoever 'holds the mantle,' no matter their political affiliation, THEIR language becomes the dominant language of the political arena over which they govern.

In looking at the phrase 'How are you?' in Spanish (Latin America), Brazillian Portuguese, Italian and Catalán (all Romantic languages), we see the following:

SP: ¿Cómo está?

BP: Como vai?

IT: Come sta?

CA: Com està?

As you can see, even though these areas are widely separated by geography, they share a common interrogative 'Com-' to indicate 'how' and their conjugation for 'to be' is similar as well.

They are not necessarily joined by the SAME political system, just similar political makeup (Democracy, or something turning into qualities akin to Democracy). 

 

 

 

Language does not come from only one source and evolves as the needs of its users change.  Romance langauges are variations of the orginial Latin. Other languages, German, Japanese, Farsi, etc. each have their own beginnings.  As people travel the world, they adopt words and phrases from other languages, for example: in English the selection of food items was once called 'bill of fare', but this has been replaced with the French word 'menu'.  In modern times, the language of country that invents or popularizes a new item or passtime generally is the one that makes the word universal; for example: Karioke or iphone.  

The language that we speak today has evolved from just a few original languages and are based on that language, therefore, any sub-language that has evolved from that original language will have similar word spellings, pronunciations and word meanings.  Please see http://en.wikipedia.org/wiki/English_language for a complete explanation of where your language came from and how it evolved.

Many languages have similar words because the words were borrowed or derived from a common language, or from newly derived terms, e.g. computer, television, taxi. English, for example has words derived from practically every other language in the world. Words are borrowed because of seemingly new concepts and needs, such as safari, bazaar. Cognates are words or languages which have a common "ancester". English apple and German "Apfel", for example, are cognates, as both are derived from Old English. The dictionary also defines English and Flemish as language cognates.

Many languages such as Spanish and English  share Latin as their root language. Therefore, they share many similar words.  Many Spanish words are refered to as cognates.  A cognate is a Spanish word that can be easily translated due to its similary to the Spanish word that defines it. For example, the word  tigre is obviously a cognate for the English word tiger. The word confusado is a cognate for the  English word confused. Again this goes back to the Latin roots of both languages.