Little corrections.

doc/ambiguity.txt

@@ -1,7 +1,7 @@
 Alias handling and ambiguous field detecting has been improved in FB2.0.
 
 Changes:
-a) When a alias is present on a table, that alias must be used or no alias at 
+a) When an alias is present on a table, that alias must be used or no alias at 
    all, the tablename only is not valid anymore.
 b) Fields without qualifier can now be used in a higher scope level. Own scope 
    level is checked first and ambiguous field checking is done on scope level.
@@ -12,7 +12,7 @@ Author:
 Examples:
 a)
   1. 
-    When a alias is present it must be used or no alias at all must be used.
+    When an alias is present it must be used or no alias at all must be used.
     This query was allowed in FB1.5 and earlier versions:
     
     SELECT
@@ -23,7 +23,7 @@ a)
     but will now correctly report an error that the field
     "RDB$RELATIONS.RDB$RELATION_NAME" couldn't be found.
     
-    Use this (preffered):
+    Use this (preferred):
     
     SELECT
       R.RDB$RELATION_NAME
@@ -39,7 +39,7 @@ a)
     
   2. 
     The statement below will now correctly use the FieldID from the subselect 
-    and from the updating table.
+    and from the updating table:
     
     UPDATE
       TableA
@@ -48,10 +48,10 @@ a)
     
     In firebird it's possible to give an alias by an update statement, but by 
     many other database vendors this isn't supported. These SQL statements are
-    now better interchangable between other SQL database products.
+    now better interchangeable between other SQL database products.
 
   3. 
-    This example didn't run correctly in FB1.5 and earlier :
+    This example didn't run correctly in FB1.5 and earlier:
     
     SELECT
       RDB$RELATIONS.RDB$RELATION_NAME,
@@ -77,7 +77,7 @@ b)
 
   2.
     Ambiguity checking in sub-selects. The query below did run on FB1.5 
-    without reporting an ambiguity, but will report it in FB2.0
+    without reporting an ambiguity, but will report it in FB2.0:
 
     SELECT
       (SELECT

doc/sql.extensions/README.PSQL_stack_trace.txt

@@ -2,31 +2,31 @@ PSQL stack trace
 
 Function: 
 	Send to client within status-vector simple stack trace with names of stored procedures
-	and\or triggers. Status-vector appends with following items :
+	and/or triggers. Status-vector appends with following items :
 
 	isc_stack_trace, isc_arg_string, <string length>, <string>
 
 	isc_stack_trace is a new error code with value of 335544842L
 
-	Stack trace is represented by one string and consists from the all sp\trigger names 
-	starting from point where exception occured up to most outer caller. Maximum length of 
+	Stack trace is represented by one string and consists from all the sp/trigger names 
+	starting from point where exception occurred up to most outer caller. Maximum length of 
 	that string is 2048 bytes. If actual trace is longer then it will be truncated to this limit.
 
-Autor:
+Author:
 	Vlad Horsun <horsun at kdb.dp.ua>
 
 Examples:
 
-0. Create metadata :
+0. Create metadata:
 
-CREATE TABLE ERR (ID INT NOT NULL PRIMARY KEY, NAME VARCHAR(16))
+CREATE TABLE ERR (ID INT NOT NULL PRIMARY KEY, NAME VARCHAR(16));
 
 CREATE EXCEPTION EX '!';
 
 CREATE OR ALTER PROCEDURE ERR_1 AS
 BEGIN
   EXCEPTION EX 'ID = 3';
-END
+END;
 
 CREATE OR ALTER TRIGGER ERR_BI FOR ERR BEFORE INSERT AS
 BEGIN
@@ -66,7 +66,7 @@ exception 3
 At trigger 'ERR_BI'
 
 
-3. Division by zero occured in trigger:
+3. Division by zero occurred in trigger:
 
 SQL> INSERT INTO ERR VALUES (4, '4');
 Statement failed, SQLCODE = -802

doc/sql.extensions/README.derived_tables.txt

@@ -35,9 +35,9 @@ Notes:
     constants should be added with an alias or the column list should be used.
     The number of columns in the column list should be the same as the number of 
     columns from the query expression.
-    The optimizer can handle an derived table very efficiently, but if the 
+    The optimizer can handle a derived table very efficiently, but if the 
     derived table contains a sub-select then no join order can be made (if the 
-    derived table is included in a inner join).
+    derived table is included in an inner join).
     
 
 Example(s):
@@ -53,7 +53,7 @@ a) Simple derived table:
        RDB$RELATIONS) AS R (RELATION_NAME, RELATION_ID)
 
 
-b) Aggregate on a derived table which also contains a aggregate
+b) Aggregate on a derived table which also contains an aggregate
 
   SELECT
     DT.FIELDS,