It depends. You put the energy into the spell. You must "feel" the spell. You must state your intent. But all in all, I'd say that saying a spell aloud ,could give your spell an extra boost - BUT - you must Feel what you're saying. You must truly put your desire and your passion, into it. Saying a spell aloud without feeling it, won't make the spell work.
Hello, Angie Gena and 2396022 have it right;
Have you ever done something right or accomplished something and someone praised you for it (Good job! Well done! You get an "A" on this!), and you felt very excited, and you just had to tell someone about this, and as you let them know, you had an excited way about you because, you could hardly keep it to yourself?
This is a very strong, good, emotion and, is the state of being you need to be in when you state your spell. The last time I suggested this, a young lady came back and stated that she felt "jittery" somewhat "light-headed" afterwards. If, this happens, you need to ground your excess energy by a short meditation. Here is an example;
Think of a beach scene. You are sitting on a beach chaise lounge chair, under a palm tree, overlooking the great blue sea on a beach. You are alone, totally relaxed. You feel a cool sea breeze on your skin. You feel the warm sun caressing your skin. You smell the salty air from the sea. You see the sea gulls dancing in the air not far from you. You see the waves undulating coming in and out caressing the beach and wetting the sand. You hear the waves gently landing on the beach. This is a wonderful scene. Take a long deep breath through your nose and, let it out through your mouth. Do the this five times more, and you are done. WAKE UP! ON YOUR FEET SOLDIER!
Ha, ha! Anyway, you might want to play some appropriate emotional music that applies to your spell. I have played "Calling All Angels" by Train and "Magic Carpet Ride" by Steppenwolf and my spells worked ok.
Just my .02c worth from the peanut gallery section.