Uff... a hard question!!! Drawing the line between a language and a dialect is really complicated, and sometimes not even scholars are able to give the answer.
But, for me, an accent in the "tone" you give to pronounce a language, your voice's inflection. So? You can have many accents, but the language is still the same, and I think that happens with all the languages that have many countries in which are spoken.
Besides, all of this "Dialect and Language" issue, depends on several things, including political, historical, regional, national... reasons. What about Egyptian, Morocan, Algerian... Arabic v/s Classical Arabic? What about Swiss German and "Standard" German? or Catalan and Valencian? Serbian and Croatian? This is a matter of constant debate.
