Loud — Eruvin 75b
תלמוד בבלי מסכת עירובין דף עה/ב
סתם נכרי אי איתא דאוגר מיפעא פעי
The Gemara here tells us that if a non-Jew had rented a property, he would have made it known loudly — he would have bellowed, or shouted.
The Rambam (Shemoneh Perakim; based on Kiddushin 71b — cf. Rashi ad loc.) writes that the extent to which a person maintains silence is in direction proportion to the distinction of his lineage (יחוס).
The Maharal (Nesivos Olam vol. 2, Nesiv HaShesikah) finds this difficult — what does silence have to do with lineage?
He suggests an interpretation based on our Gemara (see also Chullin 113b): Since we see that non-Jews — who obviously do not possess Jewish lineage — bellow and shout (and are generally loud), it follows that the less talkative and more soft-spoken a person, the more distinguished his lineage. He explains that this is because a tendency to silence is indicative of צניעות — modesty. The word tzeni'us itself is rooted in the shoresh צנע, which means to conceal. And, as the Maharal explains elsewhere (Nesiv HaTzeni'us), people who conduct themselves with tzeni'us merit having holy children. The parents' tendency to silence leads to children who tend to silence, and the children's tendency to silence indicates that the parents tended to silence: "Therefore, curtailing one's speech — which is tzeni'us — indicates lineage. For this is the foundation of lineage, to be the progeny of tzenu'im. Hence, this person is also modest in his speech, and does not reveal matters…"