Today's English learner has wonderful options for hearing the pronunciation of an unfamiliar word. Online dictionaries typically give you an audio file, definitions, examples of the word in a sentence, synonyms, sometimes a translation, and more. Among these are:
Dictionary.com (American Pronunciation)The Free Dictionary (American & British Pronunciations)Howjsay.com (British Pronunciation)Merriam-Webster (American Pronunciation)And More.
Then, there are a multitude of stand-alone pocket dictionaries and translators plus apps which turn your cellphone into such a device. If you are an ESL student learning English with the help of the Color Vowel® Chart, the "Blue Canoe Pronunciation Dictionary" app will give you the color as well. A free version is available at Blue Canoe Learning.
Google Translate also works as a pronunciation app and there are many text-to-speech apps available. Again, if you want to use color vowels to enhance your learning, Blue Canoe also offers a free computer browser add-on so that you can highlight an unfamiliar word in a browser search result, getting definition and pronunciation on the fly.
What if you have heard a new word but don't know how it is spelled? Is there a talking dictionary where you can speak the word into a microphone and have it return the likely possibilities with definitions? There are talking dictionaries developed for the blind; however I have no experience with them. Alexa might work! She will give me definitions and translations; however I have to pronounce the term quite clearly for her to understand.