The consonant clustered is when an initial consonant is placed with one of these letters ร (r), ล (l) or ว (w). A tone mark or a top position vowel will be placed above the clustered letter, not the first letter.

However, the tone rule still depends on the class of the initial letter.

Reading 1 

Reading 2 Words with meanings

However, people usually drop the clustered ร (r) and ล (l) when we speak in our daily life. You should be aware of this.

For example: To say กลับ (klàp), we may pronounce as kàp. Since กลับ (klàp) means to return or to be back while kàp itself means with, you will need the context to help you to understand. If Thai say, จะ กลับ บ้าน (ca kàp bâan) instead of (ca klàp bâan), you should know that they mean (I) will go back home not (I) will with home.

In lesson 23, you will learn the exceptions of the clusters. But if you are eager to know right away, you can check it out at The Exception of the Clusters.