Tagging Words Using VBA in MS Excel

I am having trouble sorting this out. I have an excel worksheet. Column A of sheet1 contains about 300,000 tokens and the column A of sheet2 contains about 15, 000 tokens with possible part-of-speech tags spread on the same row with each token. Format example:

A in sheet1        (A            B    C    D     E) in sheet2
now                may           NN   MD
earth              but           CC   CJS
between            can           MD   NN
been               think         VB   VBP  VBZ  NN
think              now           NN   JJ   RB   IN
may                between       IN   CC   CJS
red                ...
between
now
think
may
now           
...

my task is to take each word in A(sheet 2), search for it in A(sheet1). If found, copy tags on its row and paste the tags in cells adjacent to all the occurrence of the words found in A(sheet1). That is, if think, between, etc. are found, then I will have this output in sheet1:

A          B     C    D   E
now               
earth 
between    IN   CC   CJS            
been               
think      VB   VBP  VBZ  NN          
may                
red               
between    IN   CC   CJS
now
think      VB   VBP  VBZ  NN
may
now           
...

I have this code that does only the searching of non empty cells in A(sheet1) and A(sheet2), check whether each word in A(sheet2) is in A(sheet1). If true, then will copy the word (instead of the associated tags) and paste it in cells in C columns adjacent to results in A(sheet1). Result looks like below instead of above.

A          B      C        D    E
now               
earth 
between          between            
been               
think            think         
may                
red               
between          between
now
think            think
may
now           
...

Here is the code:

Sub CopyDataToPlan()
Dim LData As String
Dim LData2 As String
Dim iVal As Integer
Dim iVal2 As Integer


iVal = Worksheets("Sheet1").Range("A:A").Cells.SpecialCells(xlCellTypeConstants).Count
iVal2 = Worksheets("Sheet2").Range("A:A").Cells.SpecialCells(xlCellTypeConstants).Count

For LData_counter = 1 To iVal
    LData = Sheets("Sheet1").Cells(LData_counter, 1).Value

    For LData2_counter = 1 To iVal
        LData2 = Sheets("Sheet2").Cells(LData2_counter, 1).Value
        If (LData2 = LData) Then
            Sheets("Sheet1").Cells(LData_counter, 3) = LData2
            'Selection.Copy
        End If

    Next LData2_counter

Next LData_counter
End Sub

Also, this code when I try using it above 50,000 words, it either run and hang half-way or causes overflow. My aim: I prepared data in A(sheet1 & 2) for the purpose of tagging POS tags I developed to the words in A(sheet1). Words in A(sheet2) are unique words with most probable tags for it. Many users I employed for the task are more familiar with MS Office. So, I decided to make the job simpler for them. Instead of them going through the tags of about 100 and finding a tag for a word in A(sheet1), this system will provide them with a word and all possible tags for that word. All they will now do , is to take a word in A(sheet1), look through the tags provided and select one tag meant for it. Pls! I need help. Thanks guys!