“I think … I say … my saying in this affair is …”
The Imaam, the Muhaddith, the Shaikh Muhammad Naasirud-Deen Al-Albani, may Allaah have mercy on him, said in As-Silsilah As-Saheehah (hadith no. 1173), explaining the hadith which Abu Abdur-Rahman As-Sulami narrated from Uthman ibn Affaan, may Allaah be pleased with him, in marfoo’ form,“The best of you are those who learn the Quraan and teach it …”:
“In this hadith is an encouragement to learn the Quran, that the best of the teachers are the teachers of the Quran and that the best thing a man can learn is the Quran. So would that the students of knowledge know this since there is great benefit in it. And indeed a calamity which has become widespread in this time of ours is that you will find many of the callers or beginners in studying knowledge putting themselves forward in calling [to Allaah] and passing religious verdicts and answering questions from the people when they do not even know how to recite Surah Fatihah well and nor with the correct articulation points for each letter [makharijal-huroof].
So you will see him pronouncing the letter ‘seen [س]’ as a ‘daad [ض]’ and the letter ‘Taa [ط]’ as a ‘taa [ت]’ , the ‘dhaal [ذ]’ as a ‘zayy [ز]’ and the ‘thaa [ث]’ as a ‘seen [س]’ . You will see him fall into a clear error [al-lahn al-jali]  in recitation let alone the hidden error [al-lahn al-khafi]. 
It is befitting–naturally–that he should make his recitation from memory good, so that he can cite with ease the relevant aayaat and use them as proofs in his admonitions, his lectures and his da’wah. [Instead] you will see him become preoccupied with declaring [ahadith to be] authentic and weak, and refuting the scholars and preferring some over others [from among them]. You will always hear words from him which are higher than the level he is at–so you will see him saying, “I think … I say … my saying in this affair is … and the strongest opinion in my view is …”
The strange thing about this affair is that you will not find one of them talking about a matter that is agreed upon [muttafaqun alaih] amongst the scholars. Rather, he will always–except for those upon whom Allaah has mercy–talk concerning matters in which there is a difference of opinion so that he puts forward his [own] opinion regarding it; and if that is difficult for him then you will see him [going through the sayings] giving precedence to one over the other–I seek refuge with Allaah from showing off and from the love of being heard and known.
I advise myself first and then these people secondly that the best thing a student of knowledge can start with is memorisation of the Quran, due to His, the Most High’s, saying:
“But warn with the Quran he who fears My Threat.” [Qaaf:45]
And may Allaah’s prayers and blessings be upon our Prophet Muhammad (صلى الله عليه وسلم) and upon his family and his Companions.”
 Al-Lahn al-Jali, or the apparent mistake is that which changes the form of the word, and it is called apparent because both the scholars and the common folk know this mistake. An example would be to read: An’amta as an’amti.
 Al-Lahn al-Khafi, or the hidden mistake is so called because only the scholars or those who have studiedtajwid know the mistake, not the common folk. An example would be not elongating the madd enough.
Article Courtesy: http://shaikhalbaani.wordpress.com