Fix few typos in readme. (#5967)

Author: Apsaliya

README.md

@@ -238,7 +238,7 @@ Flowable.range(1, 10)
   .blockingSubscribe(System.out::println);
 ```
 
-Practically, paralellism in RxJava means running independent flows and merging their results back into a single flow. The operator `flatMap` does this by first mapping each number from 1 to 10 into its own individual `Flowable`, runs them and merges the computed squares.
+Practically, parallelism in RxJava means running independent flows and merging their results back into a single flow. The operator `flatMap` does this by first mapping each number from 1 to 10 into its own individual `Flowable`, runs them and merges the computed squares.
 
 Note, however, that `flatMap` doesn't guarantee any order and the end result from the inner flows may end up interleaved. There are alternative operators:
 
@@ -273,7 +273,7 @@ inventorySource.flatMap(inventoryItem ->
 
 ### Continuations
 
-Sometimes, when an item has become available, one would like to perform some dependent computations on it. This is sometimes called **continuations** and, depending on what should happen and what types are involed, may involve various operators to accomplish.
+Sometimes, when an item has become available, one would like to perform some dependent computations on it. This is sometimes called **continuations** and, depending on what should happen and what types are involved, may involve various operators to accomplish.
 
 #### Dependent
 
@@ -457,7 +457,7 @@ This can get also ambiguous when functional interface types get involved as the
 
 #### Error handling
 
-Dataflows can fail, at which point the error is emitted to the consumer(s). Sometimes though, multiple sources may fail at which point there is a choice wether or not wait for all of them to complete or fail. To indicate this opportunity, many operator names are suffixed with the `DelayError` words (while others feature a `delayError` or `delayErrors` boolean flag in one of their overloads):
+Dataflows can fail, at which point the error is emitted to the consumer(s). Sometimes though, multiple sources may fail at which point there is a choice whether or not wait for all of them to complete or fail. To indicate this opportunity, many operator names are suffixed with the `DelayError` words (while others feature a `delayError` or `delayErrors` boolean flag in one of their overloads):
 
 ```java
 Flowable<T> concat(Publisher<? extends Publisher<? extends T>> sources);