From a letter to Proba by Saint Augustine, bishop

To pray for a longer time is not the same as to pray by multiplying words, as some people suppose. Lengthy talk is one thing, a prayerful disposition which lasts a long time is another. [...]

The monks in Egypt are said to offer frequent prayers, but these are very short and hurled like swift javelins. Otherwise their watchful attention, a very necessary quality for anyone at prayer, could be dulled and could disappear through protracted delays. They also clearly demonstrate through this practice that a person must not quickly divert such attention if it lasts, just as one must not allow it to be blunted if it cannot last.

Excessive talking should be kept out of prayer but that does not mean that one should not spend much time in prayer so long as fervent attitude continues to accompany his prayer. To talk at length in prayer is to perform a necessary action with an excess of words. To spend much time in prayer is to knock with a persistent and holy fervor at the door of the one whom we beseech. This task is generally accomplished more through sighs than words, more through weeping than speech. He places our tears in his sight, and our sighs are not hidden from him, for he has established all things through his Word and does not seek human words.

Church of Saint Peter, Porto Venere, Italy.