Imports System.Text.RegularExpressions
Dim lines = { "word1|word2|word3", "anotherword1|anotherword2" }
Dim input = "This word1 is as word2 as anotherword2"
Console.WriteLine("Original Text : {0}", input)
For Each line As String In lines
Dim pat = String.Format("\b({0})\b", line)
input = Regex.Replace(input, pat, line)
Console.WriteLine("Manipulated Text : {0}", input)