The answer is 'yes', but you have to learn some rules. They're not hard to learn if you spend a bit of time on them. There are some exercises in my document to help you learn at http://www.scribd.com/doc/4819629/Thai-Toolkit-betaV2

The different tone is denoted by "วรรรณยุกต์" (wan-na-yook). The level of tone also relates to combination of Thai consonant letters "พยัญชนะ" (pa-yan-cha-na) and vowel letters "สระ" (sa - ra). Level of pitch are ranging from lowest to highest tone (สามัญ (sa-mun), เอก (ake), โท (toe), ตรี (tree), จัตวา (chat-ta-wa)) For example, กา ก่า ก้า ก๊า ก๋า. Some combination may have only several forms: ไล ไหล่ ไล่ ไล้ ไหล or ไซ ใส่ ใส้ ไซ้ ใส. To know a tone of syllable, learner have to know all สระ, พยัญชนะ, วรรณยุกต์ and level of tone for each of them.