Don't talk too much, because your ignorance is greater than your knowledge. (Spanish Proverb)
What the fool does at last the wise man does at first. (Spanish Proverb)
Though the speaker be a fool, let the hearer be wise. (Spanish Proverb)
There are three "too much" and three "too little" that can bring a fool down: too much spending and too little money; too much talking and too little knowledge; and too much boasting and too little earnings. (Spanish Proverb)
The old for want of ability, and the young for want of knowledge, let things be lost. (Spanish Proverb)