If you want to put emphasis on a word in a dialogue, is then putting that word in italic clear enough, or is it better to explain. "Rubber is the biggest waste problem of France," the professor said, emphasising 'the'. versus "Rubber is the biggest waste problem of France," the professor said. Is there a preference or is it a matter of style? or is it better to use both throughout the story randomly?
No, don't use both of them randomly. I can imagine this would drive an editor a bit crazy but would also make you loose the emphasis on your emphasized words. Keep in mind to use emphasis sparingly, however. A little goes a long way. In my opinion, it is better to put the word in italics. It's just a bit clearer to understand, while your other tactic seems to me a bit weaker. I want to know how a character says a word while he/she is speaking. Not after the fact. But this is a personal preference of course.
Either italics or rearrange the sentence so the emphasis falls naturally for example 'The biggest waste problem in France, is rubber.'
There is very few cases when you really need emphasis, usually you get it across without actually needing to point it out. Trust you readers, you often need it in extremely few cases. In the few cases you need it, both methods is fine, but whats differ is the pacing. With italics you get it immediately which can be important in a fast paced scene. But describing the emphasis get more information across.
Use italics. "But use them when you want to stress what the speaker finds important, not the author."
Thanks for your suggestions. I think the italic style is easiest, but wasn't sure if the emphasis meaning would come across. To make it a bit more complicated, what if you want to describe the emphasis together with some body language? E.g., "Rubber is the problem of Europe," the professor said, knocking rapidly twice with his right index finger on the table accompanying 'the'. Would that be too complicated, or does it indeed (as I intend) "show" rather than "tell"?
Sure. I want the reader to "feel" HOW the speaker said it, and this must fit the situation. It's all about creating context and atmosphere.
You don't always need to use italics. Another way of conveying the Professor's meaning is to say: "Rubber alone is the biggest waste problem of France," or "Rubber is the singularly biggest waste problem of France," Admittedly, I think the italicised version is the most emotive as you can imagine the Professor emphasising the word for dramatic effect.
"Rubber is the,' he thumped his hand down on the desk 'problem of Europe," ? Maybe find a shorter emphasis though.
I like both. Depends on who your professor is, and how deep you want to go with him, but that last sentance you wrote actually already gives me a picture of the professor in my mind, while the first one (with italics) simply tells me what he is saying and how.
"Rubber is the problem of Europe," the professor said, knocking rapidly twice with his right index finger on the table. accompanying 'the'. Use italics sparingly or they will no longer add emphasis. It's not necessary to tell your reader the rapid knocks came when he pronounced 'the'. Trust them to be intelligent enough to work that out.
either can work, so it depends on which works best in each instance... that said, i wouldn't advise using the first method more than once!...