Classroom teachers may not be able to determine if a child has dyslexia. They may detect early signs that suggest further assessment by a psychologist or other health professional in order to actually diagnose the disorder. Letter and number reversals are the most common warning sign. Such reversals are fairly common up to the age of 7 or 8 and usually diminish by that time. If they do not, it may be appropriate to test for dyslexia or other learning problems. Difficulty copying from the board or a book can also suggest problems. There may be a general disorganization of written work. A child may not be able to remember content, even if it involves a favorite video or storybook. Problems with spatial relationships can extend beyond the classroom and be observed on the playground. The child may appear to be uncoordinated and have difficulty with organized sports or games. Difficulty with left and right is common, and often dominance for either hand has not been established. In the early grades, music and dance are often used to enhance academic learning. Children with dyslexia can have difficulty moving to the rhythm of the music.

Auditory problems in dyslexia encompass a variety of functions. Commonly, a child may have difficulty remembering or understanding what he hears. Recalling sequences of things or more than one command at a time can be difficult. Parts of words or parts of whole sentences may be missed, and words can come out sounding funny. The wrong word or a similar word may be used instead. Children struggling with this problem may know what they want to say but have trouble finding the actual words to express their thoughts.

Many subtle signs can be observed in children with dyslexia. Children may become withdrawn and appear to be depressed. They may begin to act out, drawing attention away from their learning difficulty. Problems with self-esteem can arise, and peer and sibling interactions can become strained. These children may lose their interest in school-related activities and appear to be unmotivated or lazy. The emotional symptoms and signs are just as important as the academic and require equal attention.

一般的老師未必有能力識別小孩是否有讀寫障礙。他們只能大致察覺早期的一些徵狀,然後轉介給心理學家或其他醫護人員作進一步的評估,以診斷出實際的問題。讀寫障礙最常見的警號是顛倒字母及數字。在七、八歲以前,小孩寫字有顛倒的情況相當正常,但此後便會漸漸減少。如果情況沒有隨年齡漸長而改善,就應該帶孩子去測試一下是否有讀寫障礙或其他學習問題。另外,抄黑板或抄書出現困難,也是一個常見的狀況;他們書寫的作業整體沒有條理;有時,即使是自己喜歡的電影或故事書,有讀寫障礙的兒童都未必能記得當中的內容。至於空間感弱的問題,不但會影響課堂學習,甚至在操場上也可以察覺到,因爲這些孩子大都會出現肢體不協調,進行有組織的體育運動或遊戲時會感到困難。當中,遲遲未能建立以左手或右手作主導的問題最爲常見。低年級時,學校經常會通過音樂或舞蹈提升學生的學習效能,有讀寫障礙的小孩可能會難以跟隨音樂節奏。

讀寫障礙中的聽覺問題關係到很多能力,一般而言,小孩可能會在記住及理解他所聽到的東西上感到困難。要他們記住東西的次序及一次性記得多於一個指令也不容易;詞語或句子的某些部分有時會被遺漏,使得詞語變得趣怪;要不是用錯詞語,就是把一個類似的詞語借來代用。這些孩子也許知道自己想說些甚麼,但卻找不到正確的話語來表達。

患有讀寫障礙的孩子有許多隱晦的特徵, 他們可能會變得孤僻,看起來很抑鬱,也可能出現一些異常的舉動,因而掩蓋了有學習困難的問題。他們的自尊方面或許會出現問題,與同伴和兄弟間的關係也可能變得緊張,並失去參與學校活動的興趣,看上去沒有動力甚至乎懶散。 這些情緒上的徵狀與學習上的問題同樣重要,需要我們同樣重視。