The reason why we recite a blessing on voice before eating is that we are effectively eating our voice. During meals, we use our mouths for eating, denying us the opportunity to speak. Thus when we eat, we are not only eating our food but also our voice. As enigmatically explained in Ta'anit 5b:
רַב נַחְמָן וְרַבִּי יִצְחָק הֲווֹ יָתְבִי בִּסְעוּדְתָּא אֲמַר לֵיהּ רַב נַחְמָן לְרַבִּי יִצְחָק לֵימָא מָר מִילְּתָא אֲמַר לֵיהּ הָכִי אָמַר רַבִּי יוֹחָנָן אֵין מְסִיחִין בִּסְעוּדָה שֶׁמָּא יַקְדִּים קָנֶה לְוֶשֶׁט וְיָבֹא לִידֵי סַכָּנָה. בָּתַר דִּסְעוּד אֲמַר לֵיהּ הָכִי אָמַר רַבִּי יוֹחָנָן יַעֲקֹב אָבִינוּ לֹא מֵת
Rav Nachman and Rabbi Yitzchak were having a meal. Rav Nachman tells Rabbi Yitzchak to say something, but Rabbi Yitzchak seemingly refuses to answer. Seemingly, I say, because he does answer, with a verbose oration on table manners and anatomy: "Rabbi Yochanan says that you shouldn't speak during a meal, because if you do you might swallow food with your windpipe instead of your esophagus, causing you to choke and die."
Fair enough, you might say - except that after the meal, when he finally states the idea he had refused to discuss during the meal, he spits it out in a mere four words: "Our father Jacob never died." So why did he give a ten-word lecture about not speaking that was even longer than what he was going to say?
The answer can be discovered based on a careful analysis of the practice of voice-eating in Jacob's household:
Rebecca says to Jacob, I want you to make food for your father just the way he likes. And what delicacy could be better than a voice? So she tells him:
שְׁמַע בְּקֹלִי
Targum: קַבֵּיל מִנִּי
Take my voice (Genesis 27:8)
Jacob then goes and gets the voice and brings it to Isaac, and tells him he brought him food to eat. Isaac of course knows exactly what Jacob is referring to:
הַקֹּל קוֹל יַעֲקֹב
The voice is the voice of Jacob. (27:22)
After eating Isaac confirms he understands the import of his meal:
וָאֹכַל מִכֹּל
I ate a voice (27:33)
Thus we see that Jacob was raised in a home with a clear consciousness of the importance of eating one's voice during a meal. And, as we learned from Rabbi Yochanan, eating one's voice during a meal has the added health benefit of not dying. It was due to this health consciousness, says Rabbi Yitzchak, that "our father Jacob never died." As he goes on to clarify to Rav Nachman after the meal:
מָה זַרְעוֹ בַּחַיִּים אַף הוּא בַּחַיִּים
In the same way that you, Jacob's descendant, stay alive (by eating your voice and not choking), so too he stayed alive (by eating his voice and not choking).