Being able to speak is a blessing from Allah (SWT). And just like all the other blessings, we must take care of it and use it knowingly. The Prophet (PBUH) has advised us to take heed of our tongue and say good things, this is because we will be judged on all of what we say. Stated in the hadith of Muadh Ibn Jabal (may Allah be pleased with him), that the Prophet (PBUH) took hold of his tongue and said, “Restrain this.” I asked, “Prophet of God, shall we really be punished for what we talk about?” He replied, “I am surprised at you, Mu’adh! Will anything but the harvests of their tongues overthrow men in hell on their faces (or, on their nostrils)?” (Ahmad, Tirmidhi and Ibn Majah transmitted it.)
Abu Hurairah (May Allah be pleased with him) reported: Messenger of Allah (صلى الله عليه وسلم )said, “He who believes in Allah and the Last Day, let him be hospitable to his guest; and he who believes in Allah and the Last Day, let him maintain good the ties of blood relationship; and he who believes in Allah and the Last Day, must speak good or remain silent”. [Al-Bukhari and Muslim].
The tongue steals your good deeds because of the bad deeds that it does, such as: backbiting, gossiping, slander, cursing/swearing, cursing people and mocking them and more. The messenger (PBUH) has advised us to not speak unless it is good.ْ :said) Allah (SWT) said: مَا يَلْفِظُ مِنْ قَوْلٍ إِلا لَدَيْهِ رَقِيبٌ عَتِيدٌ (Surah Qaf, verse 18) Interpretation of this verse: The children of Adam do not speak a word without a watcher with him; an angel who monitors what he says and writes it down. We are judged/held accountable for everything we say whether it is good or bad, so be mindful, guard your tongue, and say nothing but good.